TESTED: Ford Performance Cat-Back Exhaust and GT350 Valence

by Billy Johnson


The Ford Mustang may be the best-selling sports car in the world at the time of this writing, yes you read that right, but it is far from the best sounding sports car in the world. We reached out to Ford Performance for their far more attractive and aggressive M-5200-M8TBV Touring Exhaust System and GT350 lower valence with integrated quad-tips to improve the looks and sound of our S550 Mustang GT.

The S550 Mustang GT leaves a lot to be desired when it comes to the looks and especially the sound of the stock exhaust. This was a major complaint in my review of the 2015 Mustang GT. Thankfully the Mustang has arguably the largest aftermarket parts industry with countless offerings that can solve this problem for us.


Stock S550 Mustang GT ExhaustOur 2016 Mustang GT California Special is relatively stock other than the addition of the staggered Performance Package wheels wrapped in Continental ExtremeContact SPORT tires and an actual, real OEM carbon fiber GT350R wing that is manufactured by Multimatic. We were looking forward to replacing the boring and anemic looking stock exhaust.

With so many options on the market, it can be overwhelming and difficult to make a decision. One of the most important things when modifying any aspect of a car is to define what the goal and what the intended use for the car is, then do some research and make a decision accordingly. For us, our Mustang GT is a daily driver, so we wanted to make the car sound aggressive without being overly loud or drone on long drives, which can quickly get annoying and tiresome. This is a very subjective metric since everyone has a different tolerance level.

When looking at different exhaust systems, it’s important to understand the affect each component has on performance and sound. Working our way from the exhaust tips forward to the engine of a V8 Mustang, the rear mufflers are the most effective at reducing the volume of the exhaust. Forward of that is the resonator which changes the pitch and deepens the sound by reducing the higher frequencies of the exhaust. Removing the resonator gives the Mustang a higher pitch “trumpet” or “rasp” to the exhaust. Forward of the resonator are the catalytic converters. Other than emissions, cats knock down the sound (and power) of the engine quite a bit. Removing the cats alone will greatly increase the volume and usually pick up over half and often over 75% of the power gains typically achieved from long tube headers, which usually remove the cats in the process. Replacing the factory headers with long tubes further (and greatly) increases the volume and trumpeting rasp of the exhaust.


Stock S550 Mustang GT ExhaustWe can see the large factory resonator in the middle of the car followed by two massive mufflers and rather boring exhaust tips which flank a body-colored ‘diffuser’.

Since our primary goal is to have a comfortable daily driver that sounds more sporty, and with our preference of the trumpeting rasp found in most modified Mustangs and somewhat similar to a GT350, rather than a deep throaty burble, we decided on eliminating the deep sound-producing resonator with an X-pipe, keep the stock headers and cats intact and go with the quietest muffler possible. The Ford Performance by Borla M-5200-M8TBV Touring Exhaust System (designed for 2015-2017 Mustang GT coupe & convertibles) fits this bill by using their quietest muffler in conjunction with a resonator replacing X-pipe. Combined with the use of the GT350 quad exhaust tips and lower valence, I was sold.

I have to admit that I’m pretty fond of the GT350/R and especially the looks of the quad exhaust, not just because I’ve been fortunate to be involved with the development of the GT350 road cars and winning the 2016 IMSA Continental Tire Sports Car Championship in the GT350R-C racecar with Scott Maxwell, but because (as an objective car guy) I feel it’s one of the best looking and driving Mustangs of all-time. Ask anyone who owns or who have driven one, read the media reviews, or simply look at how many BMW and Porsche enthusiasts that bought GT350s, who would never have imagined owning a Mustang, and it’s pretty easy to see it’s a special car. I think it’s great that Ford is offering this GT350 valence and exhaust combo, and I personally don’t have a problem with people trying to improving the aesthetics of their cars with (high quality) components, short of simply slapping an AMG or ///M badge on a base car.

To kick off the exhaust swap, we first stopped by our friends at Palm Beach Dyno to get a baseline of our relatively stock Mustang GT before installing the new Ford Performance exhaust.  Palm Beach Dyno specializes in tuning late model Ford vehicles at their shop in Boynton Beach, Florida as well as remotely to cars all over the world. Since they know these engines very well, they were a great choice for us to accurately test and validate the performance gains of our exhaust.


Palm Beach Dyno S550 Mustang GT BaselineWith our car strapped down, we turned the rollers for the first time on our stock powertrain 2016 Mustang California Special.
Page 1 of 10 Next Page
Bookmark and Share
Monday, September 11, 2017 5:55 AM
Is there a way to cut the smaller diameter muffler pipes shorter so they can't be seen looking from the back? Or weld some real tips? Valence looks awesome, but the smaller tips inside the big ones throw off the look.
Monday, September 11, 2017 8:19 AM
The original 'diffuser' is a joke. It's more a piece of plastic that resembles the rear section of a diffuser, than a real diffuser. I guess it's for people that like to say that word, to sound like they know something about aerodynamics.

"Hey, I see that weird thing attached to my bumper?"
"That's my diffuser, it makes me go real fast!"
Monday, September 11, 2017 8:39 AM
"diffusers" are often more aesthetic than functional. I've learned designers find various things aesthetically good. See Honda Civic and the bizarre black plastic honeycomb panels everywhere. I guess they are suppose to resemble vents and therefore 'look' fast?

Anyway, the rear of the Mustang looks way better with the updated lower valance. Torque gain everywhere and 30lb weight reduction is great!
Monday, September 11, 2017 9:30 AM
@Kaane - yes you can, but the muffler pipes are the proper length to end right where the faux tips starts. You don't really want there to be a big gap that allows hot exhaust gasses to heat up and melt the plastic valence. If you want to weld on real tips, there are plenty of quad top exhaust out there that are less expensive.

@ginsu - agreed. Most cars have fake scoops, vents, inlets, and aero "inspired" devices. All styling guys that aren't engineers or know how things work.

Monday, September 11, 2017 1:31 PM
so why is nobody hating on the fake exhaust tips the way everyone does when an IS-F shows up?
Mike Kojima
Mike Kojimalink
Monday, September 11, 2017 3:56 PM
It's not as fake
Monday, September 11, 2017 3:59 PM
how do you figure that? look just as fake to me... they're attached to the bumper and not the exhaust
Monday, September 11, 2017 4:09 PM
The "fake" exhaust tips are more about alignment of the tips than anything, and keeping them from bouncing around in the valence. The tips on my FR-S are always out of alignment no matter how much I adjust them. You can always paint the actual exhaust tips flack black so they aren't so obvious. BTW I've seen this fake exhaust look on high-end Mercedes as well.
Monday, September 11, 2017 4:19 PM
I know, tons of car have fake exhaust tips, but for some reason the IS-F is the only car that gets hate for it... I've never heard anyone mention anything negative about any other car with fake tips, but its always in the first 5 things that come up when talking about an IS-F

Monday, September 11, 2017 4:32 PM
Ah, for $2K I'll get Power Pack 3 and pick up a whole lot more horsepower than this nets you for less money.
Monday, September 11, 2017 4:58 PM
Warmmilk must own an IS-F. Part of it is due to the "unique" shape and exhaust tip layout of the IS-F. The GT350, Mercedes, etc... Tend to be more in line with a real exhaust tip.
Monday, September 11, 2017 5:32 PM
haha, I don't actually. I owned an IS350 for a few months, most boring car I've had. So I don't hold the IS-F in any special esteem. the whole "lets hate the IS-F for fake exhaust tips even though tons of other cars also have them and we don't care" bandwagon has annoyed me since the first time I heard about it.

I just don't get it, why is it fine for a Mustang (have owned one of these as well) but the IS-F is an inferior species of car because of it.

you bring up the stacked thing instead of side by side. if thats the case, then everyone should say they hate the stacked exhaust tips... not for them being fake.
Tuesday, September 12, 2017 8:06 AM
Oddly shaped ovaled stacked fake tips are 3 strikes against it vs good looking normal shaped fake tips. I think it's the compounded factors that make it such a point of conversation.
Wednesday, September 13, 2017 2:39 PM
Stacking one design faux pas on top of another is never a good idea. Doing it in triplicate is really asking for trouble.
Post Comment Login or register to post a comment.

MotoIQ Proudly Presents Our Partners:

© 2018 MotoIQ.com