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2015 GT Mustang Build

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Table of Contents
  1. Build Video
  2. Parts List
  3. Video Transcript

Take a look as we give this 2015 Triple Yellow GT an upgrade to improve the look, sound, and handling on the streets. Watch as we install the Eibach Sport Spring Plus Lowering kit to give it a much more aggressive stance and get rid of the factory wheel gab while still keeping the classic muscle car rake. Next, we update the appearance and add the Roush rear diffuser. Finally, we give this GT the Corsa Extreme 3" Catback with black quad tips to truly wake the neighbors.

2015 GT: Loudest Corsa Exhaust + 1.5" Lowering Springs Install!

What's up, guys? Justin with americanmuscle.com. And in the shop today, a really cool looking 2015 triple yellow GT for a few parts that will help increase the look, the sound and more importantly the handling capabilities of the already pretty stout performance pack GT. Now this car came to us with a couple of basic performance mods already in place such as long tube headers for instance but was pretty much stock otherwise. The goal today, lower the car, get rid of that ugly factory wheel gap and improve the handling with a couple of parts from Eibach, add a very cool Corsa quad-tip exhaust system with the help of the Roush rear valance. Now we don't have a ton of work to do on this car but there is some work involved, so let's get to it.

We knew we wanted to go low with this particular build, so that made the spring selection an easy one. We ended up installing the Eibach Sportline springs which are known to be one of the lower spring offerings available in the aftermarket, not just for the S550 but also for the previous generation Mustangs as well. Now I like these springs for a few different reasons. First and foremost, I love a low aggressive stance and these things are certainly gonna deliver. You're looking at 1.5 inches lower upfront, 1.3 inches in the rear, which I know doesn't sound like a whole lot, guys, but the reality is with these newer S550s it doesn't take a lot to make a big impact.

Secondly, guys, because the front is gonna be considerably lower than the rear, you're gonna get plenty of rake which is that old school iconic muscle car stance. It looks really good on those old hot rods, and guess what? Might even look better here on the newer cars. Now we're not doing any wheels and tires with this particular build here guys but if we did a great way to set off that lowered stance or that rake stance by putting a big set of meats in the rear just really sets it off in my opinion.

Now the Eibach Sportline springs are a progressive rate spring guys and what that means is the springs are gonna progressively get firmer the harder they are pushed. I like these for a streetcar because they're gonna be pretty comfortable every day on the street thanks to that initial spring rate, but once you start driving this car a lot harder in the turns, that secondary rate is gonna kick in, gonna help keep the car flatter in the turns throughout and help reduce some of the body roll that can sometimes be a tad excessive with these cars in stock form.

Helping us further reduce that body roll I just talked about, we also installed Eibach's front and rear three-way adjustable sway bars. Now full disclosure, guys, Eibach actually packages together the lowering springs and the sway bars here in one convenient package, in this case known as their Sport-Plus suspension kit and this is just a great way to help new GT owners lower their car, improve their stance and improve their handling with taking all of the guesswork out of the equation.

Now if you like the idea of one of these prebuilt suspension packages for your own GT but maybe you don't want to go as low as the Sportlines here, Eibach does also offer a Pro-Plus suspension kit, gonna be a smaller drop overall, thanks to the Pro kit springs but again, you're getting the same kind of idea here. Springs and sway bars all included. Now I do really like the idea of one of these kits, again guys because it is taking all of the guesswork out of the equation for you, instead, these parts are designed to work together from Eibach. Now I truly feel here guys that installing a set of sway bars like we did here with this car is just one of those mods that you're gonna notice right out of the box. Now the difference in handling and steering feel are gonna be completely noticeable once you hit the streets, especially even more so when you pair them up with an aftermarket set of lowering springs like we did here with this '15 GT. Honestly, guys, I'm really curious to see the difference in handling that this kit is gonna provide for this car. And in order to do so, I will be taking this thing out here shortly and putting it through its paces a little bit. But first, we did install a couple other parts so let's check those out.

All right guys again, like I said earlier, this thing did come to us with a set of long tube already in place and it actually already had a cat-back installed as well. However, the owner did want to make the switch to the always popular quad-tip exhaust system which really has been taken off with the S550 crowd lately. Unfortunately, guys, it's not as easy as just buying a brand new quad-tip exhaust system and bolting it right up, you do have to make room for all those tips with a rear valance much like the older S197s. Now relatively easy and relatively affordable way to do this is by adding the Roush rear valance and that's exactly what we did here with this GT. Now this thing is only going to fit premium package equipped cars because they do come with that factory two-piece rear bumper. And as you can see, the Roush rear valance pretty much takes place of the factory plastic with the factory bumper.

There is a small amount of modification to get this thing on place here, meaning a little bit of drilling, a little bit of cutting, nothing too crazy but as you can see the end result is definitely worth it. And since this is a Roush part, the build, the materials, the fitment, the instructions, the hardware, everything is completely top-notch which is only gonna make your life a little bit easier when it does come time for the install. I do want to point out that Roush offers two versions of this rear valance here, one that is pre-drilled for the reverse sensors or backup sensors and one that is not with a slight difference in price between the two, so just make sure you order the correct one for your ride.

One thing I really do like about the Roush rear valance is that it makes way for pretty much any aftermarket quad-tip exhaust system out there which is nice because you have some options. This is a little different from that GT350 rear valance that we just mentioned which at the time of this video really can only be used with those Ford racing by Borla Systems. That's not a bad thing per se but more options are always better.

Speaking of those exhaust options, let's get to the fun stuff here and that is the system that's gonna be making a whole lot of noise here with this particular setup, the Corsa Xtreme cat-back with their black chrome tips. Probably one of the most attractive exhaust systems available in the aftermarket as that black chrome finish is just beautiful, but this is an exhaust after all so let's talk about what kind of noise you can expect when bolting this thing up. Well, like I said earlier, guys, this thing is already rocking some Stainless Works long tubes, so those working with that Corsa Xtreme which is their most aggressive system by the way, should produce a sound that will absolutely annihilate eardrums for miles around while terrifying small children and old ladies in the process. Now what that does mean for you is that this thing will not drone at all. So with all that noise, all that carnage on the outside should be relatively quiet on the inside which is a nice thing to have on your side because a lot of aftermarket exhaust companies claim their systems don't drone and rarely follow through on it. Corsa, on the other hand here, nails it. If I were to guess guys, the Corsa Xtreme cat-back with its double helix X-pipe along with the Stainless Works off-road long tube headers should be a tad on the raspy side but there's really only one way to find out.

That thing is loud. So we're in the triple yellow 2015 GT. We just wrapped up with the small build, again, just the suspension stuff, the exhaust, and the valance. We'll get to all that. But first, this thing, when I say it'll wake the dead, it will wake the damn dead. This thing is the loudest system I've ever heard. Hands down, bar none, whatever you want to say, the long tubes in conjunction with the Corsa Xtreme is just effing loud, there's really no other way to put it.

I like loud things, my car is pretty loud. If there ever is a time where things might be just a little loud or maybe even a little too loud, this is it. Maybe that means I'm getting a little older, hell, I don't know but it's loud. Oh, my God. You know the nice thing about the Corsa is, yes, it's loud, we've already established that. But inside the car, I mean honestly guys, it's not bad at all. If you were to use an Xtreme on like a stock manifold car for instance, it would almost whisper quiet inside. But since we do have long tubes on here, and again since this is the Xtreme with no cats, but at the same time you could easily carry on a conversation with somebody in here. Meanwhile, on the outside you're just melting faces left and right. It's awesome. Oh my God.

But why we aren't really hitting turns, it's probably a good time to point out that... God, that thing sounds good. Probably a great time to point out that the springs and everything, despite the stance, rides really well, I mean we're on stock dampers still. We're still on our stock struts and shocks. Now granted you're gonna be putting a little bit more stress on your factory stuff because the Sportlines are so low and the damper is really aren't valved for that or really aren't meant for that low ride height along with the firmer spring rate. So it might tax them a little quicker than the stock springs would, they might wear out a little quicker.

Poor bastard right there had his headphones on and you would have thought it was a Mack truck barreling down on him, he got out of the way quick. But the ride height on this thing, just muah. I mean, it's perfect, absolutely perfect. It's low and it looks really good but at the same time it rides really good still. A lot of times when you go this low, you sacrifice your ride quality, that's not the case here. Rides great, I mean it's definitely a little firmer than the factory stuff, there's no denying that.

All right, guys, I finally got to a road where I can have a little bit of fun here, at least. This thing feels healthy in turns. Really going through that about 70 without breaking a sweat. God, this thing sounds great opened up. Just in any gear too. Ready? As if a yellow car couldn't get in trouble enough, one that has like atomic bombs coming out of the frigging exhaust system. Oh, and it rides great on the highway. I'm really impressed with these springs.

Yes, yes. I know I'm that [inaudible 00:10:45]. Tough being a Mustang owner sometimes, you know, I'm just trying to have fun. A couple of turns here guys, let's see how this thing feels a little bit. Very flat. Very flat. I love it. Feels great. Oh yeah, feels good, feels really good. Well, guys, this is a smaller build in the grand scale of things right in regards to overall parts. We only installed a few things but overall the impact has been huge. I mean let's run 'em down, right? Ride height, check. This thing is sitting really nice, it looks absolutely amazing even with the stock performance pack wheels. Handling this thing has definitely improved already even though we really haven't pushed this thing or beat the hell out of it too hard in the turns, you can just immediately tell things are a little tighter overall. The sway bars in conjunction with the springs are one of those mods that you don't have to wonder if it actually is doing its job because you feel it, I mean there's no denying the improvement in handling at least capabilities of this thing in regards to body roll. And then last but not least, the exhaust, the star of this build, right? If you're a fan of loud things, you want your car to be the loudest on the block, this is what you need right here. You need a set of long tubes, no cats, and a Corsa Xtreme system. The appearance too man, I mean, the Corsa quads look amazing, totally transformed the rear end and the Roush valance, you know, made it all happen, but overall, simple build but with big results. And I think I'll it with one more gear pull, why not? Guys, we hope you enjoyed this one, I know I did, my earbuds certainly did. And for all things Mustang, keep it right here at americanmuscle.com.