Review & Install Video
Hey, guys, Stephanie with americanmuscle.com, here with the KONI Sport Adjustable Shocks and Struts and Eibach PRO-KIT Lowering Springs, fitting the 2015 and up S550 GT Mustang. The pairing of the KONI Adjustable Shocks and Struts and the Eibach PRO-KIT Lowering Springs is gonna be a good option for the S550 GT owners who are looking to push the handling performance of their car, but still maintain a comfortable ride quality as well. This setup is a great option for the street cars and the daily drivers that occasionally see some track time.
If we start by looking at the springs, these are the Eibach PRO-KIT Lowering Springs. They're progressive rate springs, which concentrate on providing balance at all times in order to improve handling. They're gonna lower the car just over one inch in the front and one inch in the rear. The drop will change slightly, depending on if the car is a coupe or a convertible, due to the weight differences between the models. Now, this drop's gonna eliminate a lot of the wheel gap that the GT has from the factory, and it's gonna leave the car sitting just above the tires. A one-inch drop is pretty standard across the board for the S550, and a one-inch drop is pretty significant for these cars.
Lowering springs have a big impact on the S550, so they can completely change the looks of the car. But at the same time, a lowering spring isn't always just about lowering the car. Any lowering spring can lower the car, but the Eibach PRO-KIT is designed with handling in mind as well, which makes them a great choice for those that are concerned with improving handling and keeping as comfortable of a ride quality as possible. Now, this isn't a huge drop, so if you are looking for more drop, Eibach does have the SPORTLINE springs that will drop a half-inch more, but those are gonna ride differently than the PRO-KIT. They're just a more aggressive spring all the way around, and they also aren't available pre-kitted with the KONIs. You will need to purchase those separately.
And I said that the one-inch drop with the PRO-KIT is significant for the S550s, and I mean significant in both looks and performance changes. This drop will lower the car's center of gravity enough to have handling benefits and some traction benefits. Squattle will be reduced during acceleration, and so will some of the wheel hop that the car has. The springs are also gonna help with the body roll in the corners and nosedive under hard braking. All of this means that these springs are, generally speaking, going to tighten up and improve handling in nearly all aspects.
The PRO-KIT is also a great option for the daily drivers out there. They aren't gonna drop the car so low that it's difficult to drive places, but they are gonna drop it enough to improve looks and handling. They're also that progressive spring that I mentioned earlier, so they aren't gonna have a harsh ride quality, and that's why I consider these one of the best springs for the dailies. I would consider the ride quality nearly equal to the factory ride quality, slightly stiffer, but nothing to complain about, and I have nothing negative to say about it.
Now, I do wanna say that, a lot of times when you're shopping for lowering springs, you're also shopping for things like adjustable caster camber plates as well. In this case, I wouldn't say that the caster camber plates are required. The drop is only just over one inch, so in all reality, the ability to get the alignment within spec is still there with a small drop. If these were the SPORTLINE springs and you'd be dropping more like one and a half inches, I would suggest the caster camber plates. But it never hurts to have adjustable caster camber plates, though, so if you've got the extra cash, I'd say go ahead. They just aren't required in this case.
Now, when it comes to the KONI Adjustable Shocks and the Struts, these are adjustable components, and what that means is that you can adjust the rebound dampening to make if stiffer or softer. And these are all on-car adjustable, so you can do this without having to take things apart. Your adjustment points are gonna be right here at the top. KONI does include a tool that comes in a hardware pack that contains the knob, which is right here. Turning clockwise softens the dampening, and counterclockwise stiffens it. The cool thing about this is, if you have a street car that you wanna take to the track or the strip or you wanna autocross it, whatever it may be, you can have one setting for street driving and another for performance driving.
Besides having adjustable dampening capabilities, these are an upgrade over the factory struts and shocks in other ways. The big difference between these components and the factory ones is that these have a larger diameter piston in them. The larger piston will give better dampening and rebound when you compare it to the stock shocks and struts. Now, this means better street performance. These have the standard twin-tube gas pressure design and a steel body. As of right now, these are the only adjustable shocks and struts for the S550 that are currently available.
Now, if you've lowered your car, upgrading to an adjustable setup like this is really gonna be beneficial to you. A shock and strut with this setup is designed to work with lowered cars, so it's gonna ride better than the factory components as long as you have them adjusted properly, that is, even if your stock ones aren't blown out yet. These shocks and struts are capable of working better with a lowering spring. They're better suited to work with the firmer spring rates and the lower ride height. The internals of the factory components are not set up to take the abuse of a lowered ride height like these shocks and struts are.
Now, moving on to price, you can expect to spend between $900 and $1,000 for this kit. This is a price break, compared to if you were to purchase all of these components individually, so it's nice that they're kitted and you get a little bit of a price break here.
The install here is gonna be your normal spring and shock and strut install that should take about four hours to complete, and I'm gonna call this a two out of three wrenches on the scale. You will need a spring compressor, and a lift would help you out here as well. You are gonna need to get down to the spring and strut assemblies, so everything like the wheels, the brakes, the ABS lines will need to be moved out of the way so you can pull the assemblies out of the car. The spring compressor will help you remove the spring from the strut and install the new front springs, which are compressed and installed the same way. The new strut assemblies go back in the same way the old ones came out, and the install's the same for both sides.
The rear is where things will go a little bit differently, but nothing crazy here. Essentially, the IRS subframe will be dropped, along with the rear shock mount, so you can slide the rear shocks and springs out. Just like the front, the rear springs and shocks install the same way they're uninstalled. There's no surprises here. The new bump stop slides onto the shock followed by the factory dust boot. The new springs can be installed, and the IRS subframe can be bolted back up, and that's about all it's gonna take. You might find that, if you play around with the adjustable shocks and struts some until you find some settings that you like... And I didn't mention this earlier, but a fresh alignment after the install is always a good idea.
So now that we've got this all installed and ready to go, we can take the car out for a drive and talk about the differences that you can expect to see.
All right, guys, so we have the springs and the adjustable shocks and struts installed on the car right now, and we are taking it out to actually test the theories that we talked about back in the shop. So, honestly, I'm expecting a pretty big different out of this car over the stock suspension. Stock suspension, honestly, it leaves a lot to be desired in the performance aspect, and sometimes it makes me a little bit nervous, especially in corners. It has a ton of body roll, which is a lot of movement in the car, a ton of nosedive. I can tell already. We just pulled out. We're not even on a main road yet. I can tell already the car feels a lot different.
Now, I did say that these two are a really good combination for a street car and for a car that sees occasional track time. And right away, right off the bat, I'm still gonna stick with that. The car, I can feel that it rides stiffer, but it's not stiff at all. It's not an uncomfortable ride at all. Honestly, it's not much stiffer than factory, but already I can feel a big difference.
Now, we didn't really play a whole lot with the adjustable shocks and struts, and you do have a pretty good range of adjustment with those. We kind of set it right in the middle. We're not really setting up for anything. We're not really setting up for a track. I didn't want them too soft, because actually I personally don't like too soft of an adjustable shock and strut. It doesn't really give a good driving experience, in my opinion, so we have them set pretty much in the middle. So you can customize this and change how you want it to ride.
All right, so we're kind of getting it in a little bit. I got a little of speed there, because this road isn't the smoothest road, and I actually wanted to feel how this setup handles bumps, bruises, changes in the road surface. And this setup, I feel, is handling the bumps and the changes in the road surface really, really well, actually even better than I thought it would. So me personally, for street driving anyway, I feel like the adjustment that we have on the shocks and struts is just about right.
Now, if I were taking this to a track or to a drag strip, I would definitely change some things before I made any passes or took any laps or things like that. But that's the beauty of a setup like this, is that you can have such a comfortable ride on the street. You can have a system that's going to handle bumps and changes in road surface really, really well and give you a great ride quality and be extremely comfortable for a daily driver. But when you wanna have some fun, it's really easy to change a few things and change how the car is gonna perform for you.
So I kind of get a little bit nervous with the S550 chassis on a stock spring when I really wanna start getting into some cornering. I feel like the car has a lot of body roll, it's very unstable. But the job of this kit is to actually keep the car centered and keep it strong and feeling great so you can go into corners, you can get more handling performance out of the car. The car is more responsive. I can tell right away, getting in this car and just doing the little bit of driving that I've done already, the center of gravity, even though this isn't a huge drop... Like I said before, the S550 chassis doesn't need a huge drop to get performance gains and looks gains. I can tell that the center of gravity is lower, the car feels way more centered, way more stable, and we're just talking about doing adjustable shocks and struts and lowering springs that are gonna lower you about an inch all the way around. I mean, honestly, it really doesn't take much to get these cars performing a lot better suspension-wise.
So I can feel already the car is with me a lot more. It's way more responsive steering-wise. It feels glued to the road, I'm not noticing any nosedive, and I feel like the car is hooking better. I mean, I haven't really done any hard launches, but I did squeal the tires a little bit. I'm not gonna lie. I got on it a little bit. It spun the tires. There wasn't any terrible, aggressive wheel hop. There's actually no wheel hop at all. The car just spun. So, to me, that's a huge improvement over the factory.
So I'm not sure how much you guys can hear, but another nice thing is that sometimes some cars can get loud when you start to lower them. Inside the S550, it's still calm, it's still quiet. We don't have a rough or jarring ride. The roads aren't smooth. I am changing a lot of road surfaces, so I'm changing from different types of pavement. We're about ready to go through some corners right up here, so I want to lay in this thing just a little bit just to see how it's gonna respond for us and see about that body roll. None, none at all. Huge improvement over the factory setup, to be honest with you.
I did that in fourth gear, and then I even had a fifth gear shift, and the car didn't hesitate at all. It was right there with me the entire time. It felt glued to the road. I wasn't nervous at all. Like I said, I get nervous sometimes with the factory suspension because there's so much body roll. I don't trust it. And then that kind of sucks, to be honest with you, when you wanna have fun driving. But you can't because you feel like you're always gonna break loose any second because you're fighting with body roll. And I don't feel any of that fight right now. So, like I said, super response with even just these small changes in the steering. The car is very responsive. Now coming down to a hard braking situation. I don't even have...I felt no nosedive at all, none, felt completely gone.
All right, guys, so that's gonna wrap up this video for the KONI Sport Adjustable Shocks and Struts and the Eibach PRO-KIT Lowering Springs. If you guys are interested, you can always head over to the website and check these out more online for yourself. And for all things Mustang, keep it right here at americanmuscle.com.