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X-Force Varex Cat-Back Exhaust (15-17 GT Fastback)

Market Price $1,550.99 You Save 13% ($201.89)
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    Features, Video & Details

    • AmericanMuscle Exclusive
    • Varex Cat-Back with "Adjustable Sound"
    • Street Mode, Race Mode and Anywhere in Between
    • Electronically Controlled
    • Mid-Pipe Resonator and Adjustable Chambered Mufflers Included
    • Durable Stainless Steel Construction
    • 3" Mandrel-Bent Tubing
    • 4" Polished Slant Cut Tips
    • Direct Bolt-On, No Cutting or Welding Required
    • (2) Remote Control Key Fobs Included
    • Fits 2015-2017 GT Mustang Fastback Models Only

    Review & Installation Video

    Review & Install Video

    Justin: Hey guys, I'm Justin with and this is my detailed review of the Varex Catback Exhaust system from X-Force, available for your 2015 and newer Mustang GT. Now you should be checking this thing out if you're after a new catback for your GT and you want to have the ability to change the sound and the loudness of your exhaust from inside the car, and I think that's going to be the biggest appealing factor here with the Varex from X-Force. Now you should also be checking this thing out if you're after a top-quality system in regards to build and material and you don't mind throwing down a little extra money to get all of these things. Now X-Force is a relatively new company here stateside, but they've actually been pretty popular and well-established down in Australia, where the company itself originated. Now the Varex here is the X-Force's bread and butter. It's her patented system. It originated back in 2009 and 2010, but the company as a whole have been gaining a lot of recognition and a lot of popularity here, again, stateside thanks to the system like the Varex and their soon to be released long tube headers. Full disclosure, guys, I actually reviewed the S197 Varex Axelback a little while back and I thought it was something that was going to be a gimmick product. Something that was going to be cool in theory but poor in execution, and honestly I couldn't have been more wrong. The Varex works very well and sounds pretty damn good. Now the truth is, a lot of companies have tried the tunable exhaust thing with varying levels of success, and in my opinion the X-Force is one of the first companies to really nail the design from the execution down to the delivery, but of course ROUSH did a great job as well with their active exhaust systems for the S550. Getting into this system a little bit further here, guys, I think you'll find the centerpiece for this catback are these patented Varex series mufflers here, which do feature this built in butterfly mechanism actually built into the muffler itself. And that's going to operate much like a more modern cutout would. Basically there's a flap in there that opens and closes, and all of it's controlled by the included remote. Unlike those traditional e-cutouts that are generally fully open or fully closed with no options in between, the Varex is going to give you some options here thanks to the adjustment. And as Varex puts it, it's going to give you essentially five mufflers in one. This is achieved by opening that butterfly valve in different increments, changing your sound as you go. So what does this all mean when it comes to your overall sound and volume? Well as you guys heard with the sound clips earlier on here, the difference in sound between these different options is very impressive. Now for starters, with the valve fully closed this thing is very, very quiet. Very similar to what you might find with your factory muffler still in place. Maybe a touch louder, but not by much. However, with everything opened up it's a different story entirely here with the Varex. The sound really does come to life and it's a great sound at that. Nice deep tone overall, no real rasps to speak about here, guys, and a decent amount of volume. So with everything closed up, again, you heard the sound clips, I'm willing to give it a one out of five on my one to wake the neighbor scale here. Very stock sounding setup. But when you do open the Varex completely up, again it does come to life, so that number easily shoots up to a three, maybe even a four out of five again on my wake the neighbors scale. Not going to be the loudest system you'll ever hear, but it does have a nice, deep tone to it and the best part is no interior drone while cruising. Now I can think of several reasons why having full control of the sound and volume of your exhaust would be appealing. The most obvious would be to be quiet when you need it to be. So whether you're entering or leaving the neighborhood or apartment complex, maybe you're driving by Johnny Law, maybe you have your significant other in the car and they're really just not a fan of loud exhaust systems, or maybe even you're just trying to play the role of the sleeper. Whatever the case, the Varex should be able to help you out. Now that you know a little bit more about what to expect when it comes to the sound, let's talk about the build of the Varex here because you are getting more than just that adjustable sound. The Varex, again, is built very, very well. 304 grade stainless steel throughout, which, in my opinion, the best material to use on an exhaust system because it's going to be the best at reducing corrosion. Along with that 304 grade stainless, you are getting 3-inch mandrel bent tubing throughout. Very nice welds on this thing. And finally those four-inch slash cut tips embossed with the X-Force logo. Now the Varex actually does utilize a mid-muffler or mid-resonator system here in this capback, which is going to help round out the tone a little bit along with these Varex performance mufflers, which believe it or not are chambered, and that's where the butterfly valve comes in. Now with that valve fully closed, the Varex is going to act like a chambered muffler through the outside portion of the Varex itself here. However, once that valve is fully opened up, the exhaust flow is going to take the path of least resistance and at that point the Varex is essentially a straight-through flowing muffler, increasing both your sound and performance. Again guys, it's all controlled by the two included key fobs that X-Force throws in. Each one does have two buttons on it. One's going to open the valve and one's going to close it. So this does, again, give you some options here when playing with your sound and experimenting with the key fob. The butterfly valves are powered by a 12-volt power source. X-Force throws in the plug and play harness to get you guys up and running. Now what's going to happen is you're going to plug in both mufflers here using the water-resistant plugs. From that point you fish the harness inside your trunk and then run it to the center console, where it's to be plugged in. This is a total 100% plug and play install. Now before we fully get into the install here with the Varex, let's quickly touch on the price. And as you might expect, things are not exactly cheap at just north of $1300 bucks, but you do have to remember what you're getting here. That fully adjustable sound in addition to the quality 304 grade build here. Again, very solid given the price point. You also have to consider that the ROUSH option, their active exhaust, is only offered in an axelback and it's going to cost you nearly double the price of the Varex here. Just in case you guys were wondering, X-Force does throw a warranty at this thing. One year for the electronics and five years for the mufflers themselves. All right, as for the actual install itself here, guys, well I do have one small nitpick with the Varex and that is the design of the pipe. More specifically, the flanges they use to get everything bolted up. I'd say 99% of the aftermarket S550 catbacks utilize a slip-fit style system for the piping, which just makes everything going on a lot easier as far as the install. Now the Varex, again, they're going to utilize a more traditional flange here. There's nothing really wrong with that, it doesn't fit bad or anything like that, it just makes it a little bit more difficult to install compared to those slip-fit systems. That aside, the rest of this install as far as the exhaust is concerned is pretty standard in the world of catbacks for the S550 GT. A buddy will definitely make this one go a little easier, guys. Trust me. But overall you're just looking at basic hand tools here for the exhaust. Basically a socket set is all you really need. When it comes to the wiring, again guys everything is 100% plug and play here. You're going to want to first plug in the mufflers using the harness. From that portion on there's a little rubber grommet located in the spare tire area in the trunk. You can get the harness through the trunk in there and actually inside the car. From there, you just need to fish it to the center console area, where it will be plugged in to your 12-volt power source or socket. This is probably going to be your most time consuming part because you're going to want to do this right and make sure to hide that wire good so it's a clean install. I'm going to give this one a two out of three wrenches on my overall scale of difficulty. It's not exactly hard, guys, but it is a little bit more involved than a traditional catback install with the S550 GT. We do call this install two hours on the site here, but I wouldn't be surprised if it took you a little longer than that just getting this thing bolted up and, again, running that wire for a clean install. All right guys, to wrap this one up, the Varex from X-Force is a very unique product. It's giving you the ability to change your exhaust tone and volume on the fly, and they've used some really solid materials in the overall build. Now the install might be a little bit more involved and the price might be a little high for some folks on a tight budget, but if having an adjustable exhaust sounds appealing to you, you are not going to be disappointed when checking out the Varex. So be sure to learn more about this catback for your GT right here at

    Adjustable Sound. By installing a X-Force Varex Cat-Back Exhaust, you can dramatically change the sound of your S550 Mustang's exhaust from a mellow street sound to a rich, throaty race car growl or anywhere between with just a push of a button. The X-Force Varex Cat-Back features electronically adjustable Varex performance mufflers. Close them when driving through a residential area to stay low key. Then open them up to let your coyote howl while cruising down the highway.

    How It Works. Varex performance mufflers utilize a sophisticated internal electronic butterfly valve mechanism to direct the exhaust flow within the muffler. In the open position, the valve "uncorks" the exhaust flow allowing it to take the path of least resistance. The muffler then acts more like a straight-through muffler for a rich throaty race style exhaust note. In the closed position, the valve blocks the exhaust flow, forcing it through the chambered paths to produce a classic, mellow street friendly sound. This unique design is perfect for personalizing the power and sound levels of your Mustang to suit your own specific needs.

    Stainless Steel Construction. This X-Force Varex Cat-Back Exhaust is manufactured from high quality 3" diameter stainless steel tubing for superior durability and corrosion resistance. The System includes a Mid Pipe resonator and features two adjustable chambered mufflers that end with massive 4.0" diameter polished stainless steel tips. The exhaust tips exit in the stock location for impressive muscle car looks and sound.

    Direct Bolt-On Installation. Engineered to be a direct upgrade replacement, this Varex Cat-Back will easily bolt up to the factory piping without any modifications required for a straight forward installation. The control module that powers the butterfly valves can be plugged into your Mustang's 12v accessory outlet for easy plug and play operation or permanently connected to a 12v source - the choice is yours.

    Application. This X-Force Varex Cat-Back Exhaust is designed as a direct fit bolt-on upgrade for the 2015 to 2017 GT Mustang Fastbacks equipped with the DOHC coyote 5.0L V8 engine. This Cat-Back does not fit convertible models.

    Fitment: 2015 2016 2017 Details

    What's in the Box
    • (1) Passenger Side Muffler Assembly
    • (1) Driver Side Muffler Assembly
    • (1) Resonator Mid-Pipe
    • (2) Exhaust Hangers
    • (1) Control Module
    • (2) Key FOB's
    • Wiring Harness
    Installation Info
    Tech Specs
    Cat-Back Exhaust Specifications
    Piping Material: Stainless Steel Tip Material : Polished Stainless Steel
    Piping Size: 3" Tip Size: 4"
    Muffler Type: Chambered Fitment: 2015-2017 GT Fastback
    Will it fit my Mustang?

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    9 Questions / 9 Answers

    Ask a Question

    HI I just got the X force app in the phone, but I don't know how to like my exhaust to my phone. if i can use my phone to control my exhaust, that will be so cool! thanks


    • The X-Force Varex Cat-Back Exhaust will come with two key fobs which will be used to adjust the sound of the exhaust.


    Helpful (1)

    will this exhaust system fit a 2015 GT convertible with the 5/0 motor?


    • The X-Force Varex Cat-Back Exhaust (15-17 GT) will fit both convertible models and coupe models being a direct bolt on.


    Helpful (1)

    Are these available with black tips


    • At this time the X-Force Varex Cat-Back Exhaust is only offered with polished tips.


    Helpful (0)

    Is there a need to relocate oxygen sensors


    • The X-Force Varex Cat-Back Exhaust does not require the oxygen sensors to be relocated.


    Helpful (0)

    Hi, Can mufflers be purchased alone like axle back system?


    • X-Force unfortunately does not carry an axle-back system or just the mufflers separately at this time.


    Helpful (0)

    Will this cat back fit a 2011 ragtop?


    • This catback will not fit a 2011 Convertible GT.


    Helpful (0)

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    Customer Reviews (12) Write a Review

    Overall Rating 4.2

    out of 5 stars

    Installation Time:Full Day

    Installation Cost:$250-$500

    • Loudness / Volume 2.916667 2.9
    • Exhaust Note 4.083333 4.1
    • Fit & Finish 4.583333 4.6
    • Bang For Your Buck 4.083333 4.1

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      July 03, 2018

      Grate sounding exhaust

      Sounds good when fully open and not extremely loud. If you want louder, add an x-pipe to it. Works better with the box controls.


      Year: 2016 Submodel: GT

      Helpful (0)

    • 3/5

      Installation Time: Afternoon

      June 06, 2018

      X-Force cat back kit

      I had a competitors brand cat back and it was LOAD-DRONE CITY. Then went with X-Force. Great sound adjustability is great good quality. My only complaint is it is really not load enough. Would like to see an option from X-Force to replace the resonator with just an x-pipe or better yet an H-pipe. Would I buy again? Absolutely! I love it!


      Year: 2017 Submodel: GT

      Helpful (1)

    • 4/5

      Installation Time: Afternoon

      April 21, 2018

      Too quiet

      Look in the finish of this exhaust system is exceptionally excellent. The install to my friend and I about two hours so not so bad. I was a little disappointed with the sound being too low even with the mufflers are open. Instead of spending over thousand dollars on headers with. I bought an x pipe instead with a resonator delete. Made a huge difference. I wish they made this exhaust system without a resonator from factory.


      Year: 2016 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      September 21, 2017

      Awesome exhaust

      This is a great system you can have the exhaust loud and when you need it quite you can do that too. Plus the Shelby models have a similar system system. Awesome Exhaust!


      Year: 2015 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      September 17, 2017

      Sounds so good

      I bought the 2014 style axleback and custom fit them on to my 16 gt, was a bit of a pain but got it to work paired with my flow master scavenger x pipe and sounds so good in full open very nice tone and good volume without being annoying like the outlaws I previously had on the car. No drone at all. Really loving the fact that I can drive out of the neighborhood at 5 in morning without my girlfriend and neighbors hating me.


      Year: 2016 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      September 12, 2017


      Super fast shipping, product was packaged great! I have the MBRP long tube headers and the fit was not good at all when trying to do it myself, but I took it to a shop and they did it in a few hours and didn't have any trouble! That was expected though because it's two different exhaust but the final product is amazing! It's super quiet when wanted and a good loud when wanted. The tone is nice and deep and sounds amazing! Highly recommend. I did the wiring myself and it took 30 minutes for a clean install.


      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      September 04, 2017

      Great tone without the Drone

      Easy to install with two people. Great quality, has a nice rumble, just would have liked it to be a little louder. I receive several compliments on the tone. Sounds really good when you crack on it.


      Year: 2017 Submodel: GT

      Helpful (3)

    • 4/5

      June 24, 2017

      Aftermarket aggressive without the drone.

      This replaced a Magnaflow Street Cat-back system which, for me, had too much drone around 2k rpm. I loved the deep tone, but the volume was too much after a while. The Varex at max volume has an aggressive tone, not quite as deep or as loud as the Magnaflow, but no drone at any rpm. It sounds great under heavy acceleration with the mufflers' butterfly valves wide open, which is how I run it all of the time. But, I expect many will say it's not loud enough. If you want to draw attention to yourself at any rpm, you should look elsewhere. With the muffler valves closed, it's quieter than stock. The fit and finish is excellent; looks almost like it was chrome plated. It's a shame it's hidden underneath the car. The way the mufflers are mounted gives you precise control of the position of the tips. My only complaint is that the inside lip of the tips aren't polished to a mirror finish; swirl marks are visible. I've seen complaints about the screw clamp that's visible on the AM site's video. But I saw it installed on other sites with no unsightly clamp showing. Sure enough, the clamp that came on my system has the screw adjust on the side of the muffler, not underneath, so it's hidden.


      Year: 2015 Submodel: GT

      Helpful (2)

    • 1/5

      Installation Time: Weekend

      May 04, 2017


      This was the worst fit and resolve ever. The muffler will not fit a convertible 2016 GT. The muffler shop phoned and AM said it should fit and then the muffler shop phoned the Varex rep who didn't realize there is a difference between a coup and a convertible. The muffler was installed all though bastardized and now makes noise when stepping on the gas. DO not buy this for convertibles no matter what AM and Varex says


      Year: 2016 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      January 10, 2017

      From whisper to roar at the push of a button!

      I honestly expected it to be louder at full open, but that is not to say that it is quiet at all. At full close, this system is whisper quiet. Once you pass 3500 RPM, it really starts to shine. It's loud, but very very smooth and extremely refined and my favorite part is NO DRONE. NONE!!! Fully closed, the interior sound reminds me of a Crown Vic, but hit the "B" button to open her up and you get a smooth healthy rumble, without any headache-inducing drone at any RPM. The quality, fit, and finish of the components is 2nd to none. This is one of the best built exhaust systems you can buy. The whole thing is highly polished stainless steel and everything bolts together with flanges and gaskets to ensure a good seal. The muffler hangers give you absolute control over the positioning of the mufflers and tips, so if you are like me and are mildly OCD about that sort of thing, fear not! You can position them to your absolute preference. My only complaint is with the wiring provided to run to the power supply. With the fittings already installed, it can be difficult to fish them through tight spaces when you are hiding the wires. But honestly, I'm nit-picking even that. If you want a super high quality stainless cat-back system that sounds amazing and has the added cool-factor of an electronic active exhaust, at just barely over half the price of the nearest competition, the Varex is the one for you. You wont be disappointed!


      Year: 2016 Submodel: GT

      Helpful (3)

    • 4/5

      Installation Time: Weekend

      October 12, 2016

      Great system but needs to be louder when open

      I wound up cutting out the mid-resonator and putting in a Borla resonator delete. It was a time consuming endevour. I wish they offered it without the mid-resonator, quiets it down too much. No point in having an adjustable exhaust if it only goes from quiet to medium. Love it now otherwise though. Hear it down the street when open and quiet as stock when closed.


      Year: 2016 Submodel: GT

      Helpful (5)

    • 5/5

      Installation Time: Afternoon

      January 19, 2016

      Top Notch Quality !

      I just got this system installed on mt 15" GT. The quality is top notch and the boxes are well packed. The instructions are a bit lacking but they give you pictures and info. A few things left to the imagination....The remotes to open and close the valves id very cool. With the valves closed it is dead silent inside the car and a slight rumble outside. With the Valves opened it's very similar to a Borla Tourning setup. A slight rumble inside enough to hear gear changes but a healthy rumble outside. 0 Drone in either setting. If your looking for loud this isn't it but it does what I wanted more rumble 0 drone


      Year: 2015 Submodel: GT Las Vegas, NV

      Helpful (6)

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