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Pypes Factory Connect Cat-Back Exhaust w/ H-Box Mid-Pipe & Polished Tips (15-17 GT Fastback)

Market Price $877.99 You Save 12% ($102.31)
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  • Item 389197

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    Features, Video & Details

    • Deep, Rich Sound with No Drone
    • Improves Exhaust Flow for More Power
    • M-80 Bullet Style Mufflers
    • H-Box Mid-pipe Included
    • Durable 304 Stainless Steel Construction
    • 3" Diameter Mandrel-Bent Tubing (steps up from 2.5")
    • 4" Polished 304 Stainless Steel Tips
    • Direct Fit Replacement Upgrade
    • Fits 2015-2017 GT Fastback Mustangs with Factory Manifolds

    Review & Installation Video

    Review & Install Video

    Hey, guys, I'm Justin with I'm here with my detailed review of the Pypes Catback exhaust system with H-box, available for your 2015 and newer Fastback GT with your choice of either polished or black tips. The Pypes H-box Catback should appeal to all S550 owners out there who first and foremost prefer that low thumping tone of an H-box or H-pipe to the slightly raspier tone of an X-pipe and prefer a good amount of volume at the same time. Now, this system should also be on your radar if you're looking to keep things reasonable in regards to price but you don't want your materials to suffer because you're on a budget. Of course since this is an exhaust after all, let's quickly talk about what kind of tone you can expect when using the H-box system of the Pypes Catback. Now, guys, this is gonna be a pretty unique system in the fact that it's going to be one of the only mid-muffler style systems currently available for the S550 GT. It's gonna offer a slightly different tone compared to a majority of the other aftermarket Catbacks which are gonna place the mufflers closer to the rear of the car. As you guys heard with our sound clip, the H-box version of the Pypes Catback is definitely gonna deliver that solid muscle car tone with practically zero rasp that I did notice with our X-box system, which you can also find here on the site, by the way. Overall, guys, I'm willing to give this thing a strong three out of five on my one to five, or one to wake the neighbors scale. There's definitely some volume there, but overall, it's a slightly more toned down version of the Pypes Catback, at least compared to their X-box version. Let's talk about price quickly here, guys, because that definitely is going to be one of the big pros when checking out a Pypes Catback. If you're familiar with the Pypes brand, then you know their systems traditionally fall on the lower side of the price range, and that is definitely the case here with their S550 offerings. In fact, this thing's gonna fall right around the $800 price point, which will make it one of the most affordable currently on the site, with only the MBRP and Gibson systems being a little cheaper. Even though this is one of your most affordable options on the site, you do have to consider what you're getting here, guys, and that is top quality 304 grade stainless steel. Nobody is giving you this 304 grade stainless at this price point, with the exception of Pypes. In fact, your closest option to get that 304 will be with a Stainless Works Catback, and that's still gonna run you a couple of hundred bucks more than this system. Again, very solid build, very solid materials for the price point. Why is that such a big deal, guys? Well, that 304 grade stainless is the benchmark when it comes to premium materials for exhaust systems. It's going to be the best at reducing corrosion. So, if your car sees a lot of salt during the winter months, it's going to help prevent that rust from forming that you might otherwise find with an aluminized steel system or even 409 grade stainless to a lesser extent. With the materials covered, let's dive a little deeper into the Pypes Catback. Again, guys, 304 grade stainless steel throughout, three-inch mandrel bent tubing pretty much from tip to tip here. You are gonna find the H-box included style crossover pipe, twin M80 bullet style mufflers here, something you're gonna see in a lot of Pypes systems, very free flowing straight through by design, and everything's going to be exiting out the large four-inch polished tips etched with that Pypes logo. You can grab those in black, if you prefer, on the site. It's just gonna cost you a few bucks extra. All right, guys, but let's focus in quickly here with the H-box system because this is really what's going to shape the particular sound with this exact system. Now, if you were to blow the top off this H-box, you'd find an H-style crossover pipe. Pretty traditional in that regard. That's gonna be responsible for producing a lower tone overall, a little less volume, and help reduce some of the rasp that you might otherwise find with an X-pipe. As for the install, well, there's really nothing too crazy to point out here, guys, as is the case typically when talking about the S550 Catbacks. You really only need a basic socket set and an impact gun to knock out those clamps securing the factory Catback. Drop that guy down all at one time. It is one piece. It can be a little tough to move around by yourself, so if you do have an extra set of hands, now would be a great time to use them. Once that factory Catback is out of the way, getting the new Pypes system installed will be just as easy, again using those same tools I mentioned earlier. In my opinion, guys, I would recommend working from front to back, basically starting at the engine and working towards the rear of the car, getting the Pypes system in place one section at a time. Save your final tighten up, though, until the very end, of course, because you're gonna want to make sure those tips are perfectly positioned underneath the bumper. Overall here, nothing crazy, guys, so one out of three wrenches on my difficulty meter. Maybe an hour or two in the shop or driveway before you're making some noise. All right, guys, wrapping this one up, there is a lot to like about the Pypes Catback with the H-box - awesome sound, awesome tone, and good volume overall, especially if you're a big fan of that H-box sound. You have to keep in mind you're getting premium materials here, guys, but for an entry level price. So that's my review of the Pypes Catback which you can find right here at

    Rich Muscle Car Sound. Add a deep rich muscle car sound to your 2015-2017 coyote Powered GT Mustang with absolutely no resonance or drone by installing a Pypes Cat-Back Exhaust. This powerful sound is achieved with the help of a pair of M80 bullet mufflers and Pypes H-Box Mid Pipe that replaces the factory resonator.

    Better Flow for More Power. Pypes designed their Cat-Back to significantly improve the exhaust flow of your 2015-2017 5.0L Mustang. By replacing the factory 2.5" piping with larger diameter 3” mandrel bent piping, a pair of straight-through bullet mufflers and Pypes unique H-Box Mid Pipe you will see a noticeable increase in rear wheel horsepower and torque.

    M80 Bullet Mufflers. Pypes M80 Bullet Mufflers feature a high-flow straight-through design. Engineered with a layer of stainless mesh around a unique internally louvered core and a lining of basalt insulation, these M80 Mufflers will improve exhaust flow for more power and sound.

    H-Box Mid-Pipe. Designed to eliminate the restrictive factory resonator the H-Box Mid-Pipe improves exhaust flow when compared to traditional H and X Mid Pipes. The combination of the H-Box and the mid-muffler design helps accelerate the exiting exhaust to create significant rear wheel power gains.

    Quality Construction. Pypes Cat-Back Exhausts are manufactured from high quality 304 stainless steel piping for strength and excellent corrosion resistance. All Pypes Exhaust Systems feature smooth mandrel bent tubing to eliminate any power robbing kinks. Complete with a set of brightly polished 304 stainless steel 4" tips, this Cat-Back also adds bold muscle car styling to your Mustang.

    Direct Fit Upgrade. Pypes Mustang Cat-Back with H-Box Mid Pipe bolts straight up to the stock OEM location with no modifications required for installation. Making this Cat-Back a direct fit bolt-on replacement upgrade.

    Application. This Pypes Cat-Back Exhaust System with H-Box Mid-Pipe and Polished Tips is designed to fit the 2015-2017 GT Fastback Mustangs equipped with either aftermarket shorty headers or the stock manifolds reusing the factory catalytic converters. Not compatible with convertible models.

    Fitment: 2015 2016 2017 Details

    MPN# SFM80MH

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) H-Box Mid-pipe With Mufflers
    • (2) Over Axle Pipes
    • (2) Axle-back Pipes
    • (2) Exhaust Tips
    • (8) Clamps
    Installation Info
    Tech Specs
    Cat-Back Exhaust Specifications
    Piping Material: 304 Stainless Steel Tip Material : Polished 304 Stainless Steel
    Piping Size: 3" (steps up from 2.5") Tip Size: 4"
    Muffler Type: Straight-through Fitment: 2015-2017 GT Fastback
    Will it fit my Mustang?
    • GT - 15, 16, 17

    Not compatible with Convertibles due to different bracing; This Cat-Back is for 15-17 GTs equipped with either aftermarket shorty headers or the stock manifolds reusing the factory catalytic converters.

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    Questions & Answers (2)

    2 Top Rated Questions

    Will other axle backs fit on the Mid pipe included in the kit?

    • We cannot guarantee that the Pypes Factory Connect Cat-Back Exhaust will work with any other axle-backs.

    Helpful (0)

    What is the interior drone like with this system?

    • With the Pypes Cat-Back Exhaust w/ H-Box you may notice some slight cabin noise. But with this new setup by Pypes there should be no drone!

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    Customer Reviews (3) Write a Review

    Overall Rating 3

    out of 5 stars

    Installation Time:Shop Install

    Installation Cost:$100-$250

    • Loudness / Volume 3 3
    • Exhaust Note 4 4
    • Fit & Finish 3 3
    • Bang For Your Buck 4 4

    • 3/5

      August 29, 2016

      If you don't mind drone, they have great sound.

      Install was a bit of a bear, and after an hour of trying to get the tips aligned in the valance, pretty close became sufficient. The sound on startup was an awesome growl and once warm the idle was a beautiful low rumble. Running through the gears brought a smile, but cruising at highway speeds gifted a headache. I had to go back to stock exhaust as I typically drive in that 1700-2200 rpm range (65 - 85 mph 3.31 gears). This system produced the virtual "inside your exhaust" tour giving the driver and passangers the experience of what it may be like sitting inside a resonator.


      Year: 2015 Submodel: GT

      Helpful (14)

    • 3/5

      August 22, 2016

      Phenomenal Sound, Undesirable Drone

      Took some time to install on jack stands, fitment is an issue as the tips do not easily align with the valance, but I blame the installer (me) more than anything. Idle sound is the best, once warm the low rumble brings a smile to the driver's face. Acceleration is phenomenal, great muscle car sound. With all these pluses I had to take it off just two days later as the drone was ear rattling. With the 3.31 gearing 65 - 80 mph was just unbearable, drive me crazy. If drone is not an issue for you, I'd recommend this system. Sound awesome whilst shifting through the gears!!


      Year: 2015 Submodel: GT

      Helpful (12)

    • 3/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      May 24, 2016

      Satisfied but not thrilled!!!

      Installation was a bit of a bear. Had to take it to 2 different shops, both had their share of troubles. Could not get tips to sit directly in center of opening (very close though). Clamps were useless, needed to weld. I like the sound/tone. Deep roar below 3000RPM (has a bit of a motor boat/American muscle car rumble). Aggressive Roar >3500RPM. Doesn't scream but sounds more throaty, which I like. Still plenty load. Give it a 6.5 out of 10 for loudness (1 being stock). Sounds very different during engine cold vs. engine warm (which I also actually like!). There is SIGNIFICANT drone in 6th gear from 1700-2200RPM which is were I float at on highway or larger roads. At times, it's straight up deafening...! Cannot hold a conversation in the vehicle during this time. Work on the drone and fine tune the fitment and I'd bump rating 1.5 stars.


      Year: 2016 Submodel: GT

      Helpful (12)

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