Free Shipping On Orders Over $49. Details

Talk to a Mustang Enthusiast
M-F 8:30A-11P, Sat-Sun 8:30A-9P
$6,000 Winner!!! Dathon C. from TN Click Here!
Win $5,000 In Store Credit Enter Now

Borla Resonator Muffler (18-20 GT w/ Active Exhaust)

Item 405808
Call a Mustang Enthusiast at 1-877-887-1105
M-F 8:30A-11P, Sat-Sun 8:30A-9P
Market Price $331.99 You Save 12% ($39.00)
Our Price

$292.99 (each)

FREE Shipping

Will this fit your Vehicle?

Select a different vehicle Help?
Update or Change Vehicle
In Stock

Ship to: Ashburn - 20149
Sorry, please enter a valid US or CA postal code
We're sorry, zip can't be updated at this time.
    Create a list
    Add to New List

    Saved - View your saved items

    We're sorry. We couldn't save this product at this time.

      Video Review & Installation

      Hey, guys. Adam here with, and today, we're gonna be talking about installing and listening to the Borla Resonator Muffler available for the 2018 and newer Mustang GT. You should be checking this muffler out if you're looking to switch out your new mid-pipe that you may already have on a Borla system installed on your new S550. This, in our case, is going on our Borla ATAK cat-back. Before we move forward at all, keep in mind you don't have to have the ATAK for this to work. You could have any Borla cat-back system or even a stock system. Aftermarket systems that aren't Borla will also work. You just got to make sure the inlet and outlet sizes match up. In this case, you're working with a 2 and 1/4-inch inlet and a 3-inch outlet.Now, as you just heard from our sound clips, this is gonna get about four out of five on our loudness meter. Now, a Borla ATAK like we have here on our '18 typically gets five out of five. So, swapping out the X-pipe that comes in this kit brought it down to a four out of five. The Borla resonator muffler is gonna swap out that X-pipe and make it a little bit more mellow-sounding, because we know the ATAK can be a little overwhelming, especially at wide-open throttle and in track mode like we have here on our active exhaust. The Borla resonator muffler does mute down some of those higher frequencies, especially at the higher RPMs, makes it a little bit more mellow and a little more tolerable. The kit is a 304 stainless steel, so if you're bolting it up to a current Borla cat-back on your S550, the quality of materials match up perfectly. And because it has that 3-inch outlet and 2 and 1/4-inch inlet, it fits with our stock manifolds.Now, if you have any other cat-back from Borla, keep in mind your sound would be a different result than what you just heard from our sound clips. We're using it on the ATAK because this is one of the loudest of the loudest, so you can drastically see the difference that the resonator muffler can make. You can also add this to your stock exhaust, but you will have to keep in mind that you got to cut your factory mid-pipe off, your factory resonator. This will definitely free up some airflow and make that situation a little bit louder. Now, if you wanna pick this up, it's gonna come in just under the $300 mark, and the install is gonna get one 1 of 3 wrenches on our difficulty meter. Now, because our cat-back is already installed, the hard part is out of the way. I'm just gonna show you guys how to swap out the X-pipe for this resonator. Again, your situation might be a little bit different, but this is just the general gist of it. Unclamping everything is gonna be pretty simple. It'll take about 30 minutes from start to finish. What do you say we get started?Tools used in this install include an impact gun, a 15-millimeter deep socket, and a mallet.Now, the first step of our uninstall is to grab an impact gun, a 15-millimeter deep socket, and we're gonna loosen up the band clamps holding our X-pipe to our factory manifold pipes. Now, your install...your uninstall rather, might be a little bit different than what we're doing here. It all depends on which exhaust you have installed on your Mustang. Now, we have the Borla ATAK cat-back that does come with this X-pipe and two adapters, one on each side to connect it to our stock manifolds. So, we're gonna be loosening up these band clamps and then the opposite end of the X-pipe pier, and we'll pull this off in one piece. But for now, let's loosen up the band clamps.Next up, we can loosen up the clamps on the opposite side of our X-pipe. Basically, what we're doing here is trying to disconnect the band clamp from the X-pipe and the stock manifold. So, we can knock it with a mallet back toward the X-pipe itself and then disconnect the two. At that point, we can lower this down and pull our X-pipe out of place. All right. At this point, disconnecting the X-pipe. Again, we're just gonna grab our mallet, and because these clamps are here with the adapter, we can use that as a point to just have this back off. You wanna make sure you have a hand supporting the X-pipe in case it does actually slip out.The next step here is to take our factory band clamp that we've removed from our stock manifold pipes. We're gonna put these on the inlet side of our Borla resonator muffler. You wanna make sure you're lining these up to about where they need to go as far as that retainer pin. There's that button, that little welded-on button, on the pipes to make sure that it retains into place. So, you wanna make sure you're putting that in approximately the right position. You can put these on the inlet here. And if you need to, grab a mallet or a hammer, and you can tap it all the way back down. I like to put it as far down as I can with the exception of about maybe an inch to leave a little bit more room for the stock pipes to fit in. Do the same thing on the other side. Those clamps, we're just gonna slide on to our Borla exhaust just to have those ready to go.Now, you can put your Borla resonator muffler in place starting with the outlet side going into the Borla cat-back. All right. You might need a helping hand to pinch the two pipes together going toward the back end of your vehicle just to get them to line up with the outlet on the muffler. From here, we can lift the whole system off and line it up with our factory manifolds. Keep in mind a pole jack is definitely gonna come in handy or a floor jack, just to jack this up and make life a little easier. Now, you wanna rotate these band clamps back so that this tab matches up with the welded-on tab on the exhaust. All right. Push that tab in to get it to lock. Now, we can tighten down the clamps. All right. Now, we can tighten up the clamps on the outlet side of our muffler. Grab your 15 socket and tighten them down.Well, guys, that's gonna wrap up my review, install, and sound clip of the Borla Resonator Muffler for the '18 and newer Mustang GT. If you're looking to get your resonator muffler, you can do so right here at

      Product Information

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


      • Improve Exhaust Notes of Borla Cat-Back
      • Boost Exhaust Flow for Better Horsepower Gains
      • Dual Inlet and Outlet Design
      • Polished 3-Inch Stainless Steel Construction
      • Direct Bolt-On to Borla Connection Points
      • Requires Borla Active Cat-Back Exhausts
      • Fits All 2018-2020 Ford Mustang GT Models with Active Exhausts


      Improve Exhaust Notes of Borla Cat-Back. If you’ve installed a Borla Cat-Back exhaust, but you want to reduce the loud droning noise, then the Borla Resonator Muffler is the perfect add-on for your Mustang GT. This Borla Resonator improves your 2018-2020 Ford Mustang GT’s overall exhaust note, making it louder and more aggressive, without irritating drone from the cat-back exhaust. This improved “growl” is perfect for your car’s “muscle car” reputation.

      Boost Exhaust Flow for Better Horsepower Gains. With a performance vehicle like the Ford Mustang GT, you’d want to squeeze every bit of horsepower from your engine as possible. With this in mind, the Borla Resonator Muffler is a great investment, because it can help improve your exhaust flow. Resonators don’t reroute exhaust gases, and this reduces back pressure that potentially frees up a few more horses under the hood.

      Polished Finish, 3-Inch Stainless Steel Tubing. The stainless steel construction of the Borla Resonator Muffler makes it a very tough, long-lasting hardware for your Mustang. It is made from premium T-304 stainless steel that won’t rust or corrode, even when exposed to the elements.

      Warranty. This resonator is also backed by Borla’s Million Mile Warranty for non-moving parts, so you’re assured that this resonator will last a very long time.

      Direct Bolt-On Installation. Installing the Borla Resonator Muffler is very easy, even for those with basic or intermediate mechanical skills. It directly bolts into the Borla Cat-Back exhaust’s connection points. This can be installed using basic hand tools, and will re-use the original Borla installation hardware from the cat-back.

      Application. The Borla Resonator Muffler is designed to be used on all 2018-2020 Ford Mustang GT models equipped with Active Valve Exhaust and a Borla Active Cat-Back Exhaust.

      Fitment: 2018 2019 2020 Details

      Borla 60661

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Resonator Muffler

      Customer Reviews (3)

        Reviews of Borla Exhaust products have an average rating of 4.8 out of 5

          Questions & Answers

          10 More Questions

          Will It Fit My Mustang

          • Bullitt - 19, 20
          • GT - 18, 19, 20