Finding the right 99-04 mustang side exhaust skirts can totally change how your New Edge looks and sounds on the road. If you've been staring at the back of your pony car and thinking it looks a little too "standard," moving those exhaust tips to the sides is one of the most drastic visual upgrades you can pull off. It's a classic look that calls back to the old-school Trans-Am racers and the legendary Roush builds from the early 2000s.
There is just something about a New Edge Mustang (that's the 1999 to 2004 model years for the uninitiated) that begs for a lower, wider stance. The body lines are sharp and aggressive, but the factory side skirts can feel a bit thin. When you swap them out for side exhaust versions, you're basically giving the car a much-needed "chin" for its midsection. It fills that gap between the wheels and makes the car look like it's hugging the pavement, even if you haven't touched the suspension yet.
Why Side Exhaust Makes Sense for the New Edge
Most people stick with the traditional rear-exit exhaust because it's easy. But let's be real—everybody does that. When you go with 99-04 mustang side exhaust skirts, you're stepping into a different lane. It changes the entire profile of the car. Suddenly, you've got these beefy rocker panels with cutouts for polished or matte black tips. It's a look that says "I track this car," even if you only drive it to the local cars and coffee on Saturday mornings.
Beyond the looks, there's the sound. When your exhaust exits right under your door, you hear everything. You get that raw, visceral V8 rumble right in your ear. It's louder, it's prouder, and it makes every downshift feel like a major event. If you're running a 4.6L Modular motor, you know those engines have a very specific, rhythmic growl. Moving the exit point closer to the cabin just amplifies that experience in the best way possible.
Choosing the Right Material for Your Skirts
When you start shopping for 99-04 mustang side exhaust skirts, you're going to run into a few different materials. This is where you need to pay attention, because the material determines how much work you're going to have to do before they're ready for the street.
Urethane vs. Fiberglass
Most high-quality skirts are made of urethane. If you can find them, get them. Urethane is flexible, durable, and can handle a bit of a beating. If you accidentally scrape a curb or hit a speed bump, urethane will usually flex and pop back into shape. It's much more forgiving for a daily driver.
On the other hand, you'll see some cheaper options made of fiberglass. Now, fiberglass can look great because it's very rigid and holds a sharp line, but it's brittle. One bad encounter with a driveway entrance and you might be looking at a crack that's a nightmare to repair. Plus, fiberglass usually requires a lot more "prep and fit" work. You'll spend hours sanding and test-fitting before it actually looks right on the car.
ABS Plastic Options
There are also ABS plastic versions out there. These are sort of the middle ground. They're tougher than fiberglass but not quite as "bouncy" as urethane. They're usually a bit lighter, too. Whatever you choose, just make sure you're prepared for the prep work. Most of these parts come in a raw finish, meaning they're not ready for paint right out of the box. You'll need to clean off the mold release agents and prime them properly.
The Installation Reality Check
I'm going to be honest with you: installing 99-04 mustang side exhaust skirts isn't always a "bolt-on" afternoon project. It can be, but you should prepare for some finagling. Since you're dealing with aftermarket body parts, the tolerances might not be as perfect as the factory pieces you're taking off.
You'll likely have to drill some holes in your pinch welds or use heavy-duty automotive adhesive (like 3M VHB tape) along the top edge to keep them flush against the body. The last thing you want is a gap between the skirt and the fender—that's a "ten-footer" car, and we want yours to look good from two inches away.
Then there's the exhaust itself. You can't just use your stock mufflers and tailpipes. You'll need a specific side-exit exhaust kit that routes the piping out to the sides. Some guys DIY this by cutting their existing mid-pipe and using 90-degree bends, but if you want it to line up perfectly with the cutouts in your new skirts, a dedicated kit is the way to go.
Handling Heat and Ground Clearance
One thing people often forget about is the heat. Exhaust pipes get hot—obviously. If your 99-04 mustang side exhaust skirts are sitting too close to the tips, or if the tips aren't aligned right, you can actually melt or bubble the paint on your expensive new skirts. It's always a good idea to leave a little bit of a "breathing room" gap around the exhaust tip, or even use some heat-reflective tape on the inside of the skirt where the pipe passes through.
And let's talk about ground clearance. The New Edge Mustang already sits pretty low if you've got lowering springs on it. Adding side exhaust skirts usually drops that side profile by another inch or two. You're going to become very familiar with "the angle" when pulling into driveways. Speed bumps will become your mortal enemies. It's a trade-off, though. The stance you get is worth the occasional scrape on the bottom side where no one can see it anyway.
Getting the Paint Right
Unless you're going for a two-tone look, you're going to want to paint-match your 99-04 mustang side exhaust skirts to the rest of the car. If you have a common color like Oxford White or Black (UA code), it's pretty easy to find a shop that can match it. If you're rocking one of the more unique colors like Bright Atlantic Blue or Zinc Yellow, you might want to have the shop blend the paint into the door and fenders for a seamless look.
Some owners prefer to leave the skirts in a matte black or "carbon fiber" finish to create a high-contrast look, especially on silver or red cars. It gives it more of a race car vibe. If you go this route, just make sure the finish is UV-protected so it doesn't turn grey and chalky after a summer in the sun.
Final Thoughts on the Side Exhaust Look
At the end of the day, installing 99-04 mustang side exhaust skirts is about making the car yours. The 99-04 generation is arguably one of the best-looking Mustang eras, but it's been around long enough that a lot of them look exactly the same. Side exhaust is that one mod that immediately sets you apart from the sea of GTs and V6s at the local meet.
It's a bit of work, and it's definitely an investment when you factor in the skirts, the exhaust kit, and the paint. But the first time you fire up the car and hear that roar coming out right next to your seat—and you see that aggressive, low-slung silhouette in a shop window reflection—you'll know you made the right call. It turns the Mustang from a cool pony car into a legitimate street-presence machine. Just take your time with the fitment, watch those speed bumps, and enjoy the soundtrack.It's definitely a head-turner.