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X-Force 1-7/8 x 3-Inch Varex Long Tube Catted Headers with Cat-Back Exhaust System (15-17 GT)

Item 390326
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$2,338.20 (kit)

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      Review & Installation Video

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Varex Full 3" Exhaust System with "Adjustable Sound"
      • Street Mode, Race Mode and Anywhere in Between - Electronically Controlled
      • Increases Rear Wheel Horsepower and Torque
      • Long Tube Header Design - 1-7/8"
      • High-Flow Metallic Catalytic Converters
      • Mid-Pipe Resonator
      • Adjustable Chambered Mufflers
      • Free Flowing Stainless Steel Mandrel-Bent 3" to 3" Tubing
      • 4" Polished Slant Cut Tips
      • Direct Bolt-On, No Cutting or Welding Required
      • (2) Remote Control Key Fobs Included
      • Fits 2015-2017 GT Mustangs


      More Horsepower and Torque. Improve the power and performance of your 2015-2017 GT Mustang by installing an X-Force Varex Full 3" Exhaust System. This X-Force Varex Exhaust features a pair of 1-7/8" Long Tube Headers and High Flow Metallic Catalytic Converters that will greatly improve the exhaust flow of your coyote powered GT, when compared to the factory setup. This System not only improves the power of your Mustang, but also improves its sound with a pair of adjustable Varex Mufflers.

      Adjustable Sound. By installing a X-Force Varex Full Exhaust System, 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. This X-Force Varex Exhaust features a pair of 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 speeding down the highway.

      How It Works. X-Force 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 now 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.

      Full Exhaust Kit. The X-Force Varex Full Exhaust Kit is a complete 3" system from headers to tips. This kit includes a pair of 1-7/8" Long Tube Headers, a pair of High-Flow Metallic Catalytic Converters, a Mid-pipe Resonator, a Cat-Back Exhaust with Varex Performance Mufflers and a set of 4" Slant Cut Tips.

      Stainless Steel Construction. This X-Force Varex Exhaust System is manufactured from high quality stainless steel tubing for superior durability and corrosion resistance. The Long Tube Headers are constructed from 1-7/8" diameter piping that merges into 3" collectors for superior exhaust flow. The rest of the System features smooth mandrel-bent 3" diameter tubing to eliminate any power robbing kinks.

      Direct Bolt-On Installation. Engineered to be a direct upgrade replacement, this X-Force Varex Exhaust System will easily bolt on without any modifications required for a straight forward installation. The control module that powers the muffler 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.

      Required Upgrade. To realize the maximum power potential that this X-Force Varex Full Exhaust System has to offer, AmericanMuscle highly recommends a Bama custom tune with a Mustang Handheld Tuner to reprogram the vehicles computer (ECU) for proper operation.

      Application. This X-Force Varex Full 3" Exhaust System is designed as a direct fit bolt-on upgrade for all 2015 to 2017 GT Mustangs equipped with the DOHC coyote 5.0L V8 engine. These Headers are intended for left hand drive applications only.

      Technical Note. Not legal for use on pollution controlled motor vehicles; intended for off road use only.

      Fitment: 2015 2016 2017 Details

      MPN# FM15-VMK-EBS

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (14)

      Write a Review

      Ratings Summary

      3.9 out of 5 overall rating from 14 customers

      Installation Time: Weekend

      Installation Cost: $500-$1000

      • February 11, 2020

        4 2016 GT - JohnA

        Total sound

        The ability to change high and low is great for parking at home and in garage with roommates and late hours... only thing is the total loud is still not that loud I think we need more boost !!

        Helpful (0)
      • July 29, 2018

        5 2017 GT - JackM

        Easy install if you take your time.

        This is a very nice exhaust. I installed the entire system in my garage on jackstands over a few days, working on it when I had some free time. In other reviews, they mention removing the AC, unbolting the trans mount, dimpling the header, leaving one motor mount bolted while jacking up the other side, using different hardware other than the factory header studs, and using header wrap. I did NONE of that and installed my exhaust. I called Xforce and was advised to not use header wrap. They said if I was concerned about radiant heat, ceramic coating is a much better option. I found a place locally that coated them for $150. They look great. I used all the factory hardware to install the headers and did not dimple anything. The only place I had a clearance issue was on the drivers side top rear stud. I removed the stud, cut about 1/2” off it, and reinstalled it. I made sure to start that one first and was able to tighten everything up with no issues. You DO NOT have to remove your AC or mess with the trans mount. With the starter and factory exhaust removed, each header took me about 1 hour to install. A stubby ratchet helps, but the biggest time savers were two Gear Wrench’s, one normal and one flat, (no angle on the ratchet end). Start with BOTH motor mount to engine bracket bolts unbolted so the engine brackets are sitting on the mounts. I installed the passenger side header first. I used a floor jack and a small block of wood and raised the engine on the passenger side of the oil pan until the trans came close to the tunnel but not pushing against it, (it is important for it to not be jacked up tight to the tunnel). Remove the motor mount bracket and motor mount. This is where it’s important to not have the drivers side motor mount to engine bracket tight. When you slide the header up in place, if you don’t have enough room to get it on the studs, you can easily push the engine towards the drivers side a little to slip the header on the studs. Once all the nuts are started, take your time on each one and use those Gear Wrenches when you need them. On the drivers side, trim that stud, unbolt the steering shaft (one bolt, very easy), and it goes faster than the passenger side. I was missing one of the bolts that clamps the tip on, its and odd size, so I called Xforce and had it in a few days. I needed one o2 extension harness for the front drivers side sensor. Kooks makes a 12” extension I found on here and you can buy it individually. I’m very happy with the sound. Closed it’s nice and quiet. Opened the car has a noticeably deeper rumble and gets plenty loud for me. If I had to do it over I would still buy this exhaust.

        Helpful (4)
      • October 19, 2017

        4 2015 GT - ManuelC Installation Time: Weekend

        A real pain to install but worth it

        The heade is one of the most frustrating part to install of my project. Afer all i wonder if removing the engine is not a better solution than do this in place. You need some new stud or bump the header a some location because stock stud won't fit. We had to wer the transmission to gain acces to some bolt, remove AC, motor mount really a pain. The rest of the install would have benn staigth if all hardware wad present, 8 bolt and nut missing from the kit, we had only 4 gasket wich cover only the cat section. We PRESUME that other joint don't need some... Sound with the flap open is loud and crisp. Very happy with that. We replace the remote by a momentanous 6 pins switch hidden in the center console. Check youtube for switch instruction.

        Helpful (5)
      • October 11, 2017

        5 2016 GT - ChristopherR Installation Time: Weekend

        Best Bang For Your Bucks

        Shipping was super fast to my APO address. Fitment was a bit of a challenge. Hand driver side header bolt issues. You have to hang the header and raise the motor to get the #7 bolt on. The driver side cat mount hits the automatic trans mount (I have a manual). All in all, it takes some work but for the money and variable exhaust it's amazing!

        Helpful (4)
      • August 04, 2017

        4 2016 GT - ChrisR Installation Time: Weekend

        Be ready for the install!!!

        NO O2 EXTENDERS I bought this full system while in sale for $1,200. That was a steal!!! The install in my 2016 PPGT was tricky. The factory header bolts are difficult as expected. However, DS number 7 had to be cut in order to get the nut back on. This could have been avoided if the nut was placed on while the header was loose. PS number 8 is near impossible. Had to turn it 1/16 at a time for nearly 2 hours. Yes we removed the A.C., starter and the motor mounts many times. Was it worth it.....oh yeah it was!

        Helpful (6)
      • July 30, 2017

        4 2017 GT - MichaelB Installation Time: Weekend

        Great sound, Needs a tuner and wrap

        Great sound and look fantastic. But needs wrap and a front pass O2 extender. The headed are tight and a little hard to get the nut on the studs for header. Would set up for a weekend with three people. Need a tuner.

        Helpful (7)
      • July 05, 2017

        5 2015 GT - Timbo Installation Time: Full Day

        Great quality, awesome sound!

        Installed this system in a weekend, fit was very good. Sounds absolutely awesome and the versatility to switch into quiet mode at the press of a button is a perfect fit for me so I can have it really tame for long drives on the freeway, etc. I would definitely recommend!

        Helpful (5)
      • June 29, 2017

        5 2016 GT - Gardner Installation Time: Shop Install Installation Cost: $500-$1000

        Excellent Manufacturer experience

        We ordered the kit for the 2016 GT Convertible. Because of the headers, we also decided to have the kit installed at a shop... You'll want 4 rolls of header wrap while you're at it... Clearances in that engine bay are tight and you want that heat to stay in the pipes. Highly recommend you hire out the header install!!! Note for convertible owners, contact the folks at X-Force directly to make sure you get the newly designed oval mufflers, along with the rear pipes that are specific to the convertible (due to the bolt on subframe connectors). American Muscle folks have been given the new part numbers at this point. I can say without hesitation that the folks at X-Force were absolutely fantastic to deal with. Customer support was great, answering the installers questions and making sure I had the correct parts to complete the setup for the convertible. Great company! Opened up, the system sounds ridiculously cool under acceleration, with no harmonic drone at any particular rpm on the highway, and then you press the button to close the baffles... completely silent. Real Deal. Couldn't be happier.

        Helpful (7)
      • June 09, 2017

        1 2016 GT - MilesL Installation Time: Shop Install Installation Cost: $1000+

        Do not buy!

        Rattles very loudly. Good sound if you can get past the rattling and clunking noise. Does NOT fit a convertible without major mods!! Buy a roush!!

        Helpful (3)
      • August 08, 2016

        5 2016 GT - Shad

        Awesome sound and power!!!

        Just like the title says. The entire system sounds great and delivers when it comes to power. The installation is very tedious and takes a ton of patience with the lack of space you have to work with in the engine bay. I did the install in a day and a half on jack stands. The setup for the active exhaust is so simple and a great feature whwn you don't want to make any noise. I highly recommend this system for anybody looking for longtube headers.

        Helpful (4)

      Questions & Answers (14 answers)

      5 Top Rated Questions

      Will this system fit on the convertible GT 5.0?

      • This system will not fit the convertible models due to the extra bracing they have under the car.

      Helpful (2)

      Is the driver side header already clearance for the steering shaft or will clearancing need to be done

      Do you have anything to Cover The Starter wire? Its too closed to the pipe exhaust... i think it gonna Burn and Melt..

      • No, we do not have anything on hand to cover the wire. Using a zip tie to get that out of the way wouldn't be a bad idea however.

      Helpful (0)

      What's the big difference between these headers and ceramic headers (like Kooks and others)? I live in Kuwait (very hot weather) Because I installed Xforce Cat-Back and now I'm searching for the best Headers for less hot.

      • For the best results against high temperatures, I would suggest the ceramic coated headers.  

      Helpful (0)

      Can I replace the mid pipe resonator with an x-pipe?

      • The midpipe resonator in this kit can not be replaced by standard X pipes for the GT.

      Helpful (0)
      Post Your Question
      9 More Questions
      how much more Horsepower and Torque dose it make? 1 answer
      What's the warranty? 1 answer
      I am very interested in the X-Force 1-7/8 x 3 in. Varex Long Tube Catted Headers w/ Cat-Back Exhaust System (15-17 GT).. But have since read a few reviews that may have changed my mind. I have a '15 gt Prem Convertible. I have read that this will NOT fit my car due to differences in braces under the car. I need to verify this before I move forward in purchasing this System. Could you confirm that this will or will not fit a '15 GT Convertible. And if not, can you recommend a system comparable to this along with the price-point. Thank you 1 answer
      I've just fitted the exhaust, but I'm scared if I wash it with pressure water will it damage the butterflies ? Or the sensor wiring and everything? And where can I get an O2 extensions are they included ? 1 answer
      Will I need 02 extensions 1 answer
      Does this system require a tune 1 answer
      will this system fit a R/H drive UK model GT 1 answer
      Will this fit a 2016 GT 5.0 automatic ? 1 answer
      What is the overall weight spec for this setup? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Passenger Side Header
      • (1) Driver Side Header
      • (2) High-Flow Catalytic Converters
      • (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

      Tech Specs

      Will It Fit My Mustang

      • GT - 15, 16, 17

      These Headers are intended for left hand drive applications only.

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