Though the S550 Mustang GT sounds good from the factory, many enthusiasts want a better tone and more volume. While changing the sound of your Mustang’s exhaust is often the main reason for getting an aftermarket kit, there are other benefits as well. A new exhaust can improve your S550's performance and enhance its style.
There are different levels and tones of aftermarket exhaust upgrades. With a wide range of options, every S550 owner can find something that fits their needs.
S550 Mustang GT Exhaust Fitment
The S550 Mustang GT has kept the same Coyote motor since debuting in 2015, just with different tuning updates. Some aftermarket parts, like mid-pipes and headers, are compatible with the whole generation.
However, cat-back and axle-back kits are not cross compatible between 2015-2017 and 2018+ models. Additionally, if you have the active exhaust system that was launched in 2018, you’ll need a specific active exhaust or non-active exhaust kit.
Axle-Back Exhaust Kits
For enthusiasts that are solely looking for a sound upgrade, axle-back kits are perfect. They’re also the most affordable option. Plus, you get to choose custom exhaust tips in the finish you want, including carbon fiber.
There are some downsides to axle-backs though. You won’t see the small performance increase you get with a cat-back. And since an axle-back kit won’t work directly with the factory components, you’ll have to cut your exhaust pipes. This can be intimidating for beginners or those without a reciprocating saw. If you don’t want to do it on your own, an exhaust shop will be able to install it at a low cost (around $100-$150). For many enthusiasts, these minor drawbacks are worth the low price of admission.
Cat-Back Exhaust Kits
Cat-back exhaust kits are the go-to choice for most S550 owners that are looking for bolt-on performance mods. This is because they provide the sound benefits of an axle-back, but also a moderate performance bump.
The added performance does come at a higher price than axle-back kits. However, there's still a wide range of options for almost every budget. Plus, you don’t have to do any cutting to install a cat-back kit since they connect to your existing factory parts. This makes them an easy project, even for novices.
Exhaust headers are for Mustang owners who purely want an increase in performance. Both long tube and shorty headers increase exhaust flow where it matters - close to the engine. By removing the factory catalytic converters and installing wider piping, exhaust gases can escape the engine more quickly.
You’ll notice a throatier exhaust note after installing a set of headers, especially long tubes. But axle-back kits do a much better job at altering the exhaust’s sound, and for a lower price.
Headers come with catalytic converters (catted) or without them (known as “off-road”). If you plan to drive your Mustang on the street, pick up a set of headers with high-flow catalytic converters. If you want to squeeze every ounce of power out of your Mustang, then a set of headers without cats will do the trick. Just keep in mind that your ride will only be legal to drive at places like the dragstrip or track.
Mid-Pipes and Resonator Deletes
Instead of installing a full cat-back kit, you can swap out your mid-pipes. Cutting is required, but it’s a cost-effective way to improve your exhaust outflow and sound. There are both resonated and non-resonated options. Some are simply a resonator delete.
Since the S550 Mustang GT has a dual-exhaust configuration, you can go with an H-pipe or X-pipe layout. H-pipes are regarded as the more classic, muscle car set-up. X-pipes have more of a European sound, with a higher pitch and more rasp.
Most mid-pipe kits are what’s called a “resonator delete.” Instead of adding a less restrictive resonator, they remove the factory one altogether. This can increase exhaust drone, but offers an easy way to get a louder sound on a small budget.
Complementary Mods for Your New Exhaust
Installing a cat-back exhaust kit or new mid-pipes will give your S550 a slight bump in performance. But a few bolt-on mods can help your engine reach its full potential. The best complements for an exhaust upgrade are a cold air intake and electronic tune.
A cold air intake will give your engine more cool air to burn, increasing horsepower. An ECU tuner will reprogram your car’s computer settings to optimize the timing and fuel ratio for better performance. Together, these three bolt-on mods are a relatively inexpensive way to make your Mustang quicker and more responsive.