MRT Axle-Back Exhaust Kit KR Stainless Steel With 4" Polished Tips Without Active Exhaust Mustang V6 2015-2017/ EcoBoost 2015-2022

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MSRP $712.78
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MRT Stainless Steel KR Axle-Back Exhaust Kit with 4" Polished Exhaust Tips for 2015, 2016, and 2017 V6 Mustangs and 2015, 2016, 2017, 2018, 2019, 2020, 2021, and 2022 EcoBoost Mustangs without the Factory Active Exhaust Option.

Transform your V6 or EcoBoost into a monster with MRT’s brand new KR Series Axle-Back Kit for your 2015-2017 V6 or 2015-2022 EcoBoost Mustang. For anyone who knows MRT, “KR” means 100% performance for your S550, complete with a head-turning exhaust note and all.

Features and Benefits:
- CNC Mandrel Bent Tubing
- 4” Polished Stainless Steel Exhaust Tips
- 304 Stainless Steel Construction
- Loud, Aggressive Exhaust Note
- Substantially Lighter Than OEM Muffler
- Vastly Improved Exhaust Flow
- Easy Bolt-On Installation
- Made in the USA

With an easy bolt-on installation, the KR Axle-Back Kit from MRT replaces your S550’s factory mufflers with an intense, aggressive sound. With a perfect fit and finish, how could you say no to picking up these muffler deletes for your V6 or EcoBoost?

Vehicle Fitment:
- 2015-2017 V6 Mustang 
- 2015-2022 EcoBoost Mustang

These pipes are designed and manufactured in the USA and made of CNC mandrel bent 304 stainless steel tubing. That means that this axle-back kit will without a doubt stand the test of time. With a loud, aggressive exhaust note, these pipes will not only improve your Mustang’s exhaust flow, but also save your Pony a few pounds in comparison to stock mufflers.

Please Note: Will not fit 2019+ EcoBoost Mustangs that are equipped with the Active Exhaust Option from the factory.

California Residents: Proposition 65 Warning

Installation Difficulty


Novice skill is required for this installation.

Installation Videos

Video Transcript

Whenever we do an exhaust video, we always get asked the same two questions. Which one sounds the best, and which one's the loudest? Well if you have a 2015-2022 EcoBoost Mustang and you're looking for the loudest thing you can possibly put on there, MRT's KR series might be exactly what you're looking for. Today we're going to install these on our 2015 EcoBoost fastback.

The MRT KR series is a light-weight, USA made, 304 stainless steel, muffler delete. Features a 4 inch polished tip, and like all axle-backs, will require cutting for installation. This is going to fit your fastback or your convertible.

For this installation today: lift or jack and jack stands, 1/2 inch ratchet, 15mm socket, tape measure, marker, sawzall, and safety glasses.

Like we said before, this axle-back will require cutting your stock exhaust to install it. Viewers of our channel are going to know, our stock exhaust is long gone from our EcoBoost Mustang. Basically what you're going to do, is where the factory muffler curves into the tail pipe, 2 inches over from the curve, you're going to mark it, and cut it straight off.

The pipe almost has a mark where you want cut. Follow the edge of the curve where it's flat, make a little mark, and that's where we're going to cut.

You want to make sure once you cut it just go back through, just de-burr it real quick, make sure there's no sharp edges.

Once you have it cut just clean up the edge, and the installation's pretty easy. Take your clamp and slide it over the factory pipe, and take our MRT KR just put it just on the edge of the factory hanger here, push back till it lines up with the pipe, and slide it over.

Once you have it adjusted in place, slide the clamp over, and tighten it down. Repeat the process on the other side and your installation's finished.

All right, now let's see how our MRT KR's sound. Definitely a deeper tone a idle. Definitely one of the louder, more aggressive sounds we've had, especially considering we have the stock catalytic and the stock resonator still on this car.

Despite how loud it is outside, the MRT KR actually isn't that bad inside. You can hear it, it's a nice deep tone, but even accelerating, I mean it's loud, but it's not nowhere near as bad as I thought it would be. That's kind of the case with all the S550 exhaust systems though. These cars are so well insulated inside that no matter how loud the exhaust is, it really isn't bad inside the car.

Now we're up to highway speeds, we're cruising right at just under 2 grand, let me get it right at 2 grand. That's 2000 rpm's, no drone at all, barely even know it's back there. I found the EcoBoost cars, especially if you keep the factory resonator in place with the factory down-pipe with the cat, there isn't a bad drone to them.

Wide open throttle sounds good. Again, like I said, not overly loud inside. I know from our original video clip that it is loud when you're actually revving it up inside the studio or even sitting outside, but when you're driving along, it's not bad at all.

If you're looking for the loudest muffler you can find for your EcoBoost Mustang, yet still want to keep the resonator and the catalytic converter to stay legal, the KR from MRT is probably the way to go. These things are loud and aggressive, really not that bad when you're driving on the highway. The installation, besides the cutting, is pretty straightforward. Even with the cutting, the whole process should only take you about an hour, so you'll be back on the road in no time. For more solution videos for your 2015-2022 Mustang, make sure to subscribe to our YouTube Channel, and check out for the best selection of 2015-2022 Mustang parts.

Vehicle Fitment

This product will fit the following Mustang years:

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