I got a great deal on Koni STR.T's and SR springs over the past several months and finally installed about 2 weeks ago. Initial impression on the street with stock Track Pack wheels & tires was the ride felt no harsher at all, however much more "locked down" and precise. Roll was definitely reduced, as was dive and squat. Hard to really tell on the street though the full benefits. That said, I got the car out to my local road course (Limerock Park) yesterday.

I was able to get in 6 track days with the car on stock suspension, and was overall quite happy. It was pretty predicable, had solid grip in the corners and under braking, and was overall fine. However, the suspension upgrades made it much better. I do not think the suspension modifications alone made the car any faster around the track, however what they absolutely DID do was make me feel much more confident in the car, which led me to pushing it much harder because I had better feedback and control. It was pretty neutral with a tendency towards understeer unless I purposely invoked oversteer through lift throttle or power exiting a corner. When the rear started to step out, it was in a more "feel-able" way, which I experienced as slower compared with stock. This was a good thing because I felt it starting, allowed the car to rotate a bit, then pulled it back in. This made me faster in most corners. Additionally, the VASTLY reduced dive under hard braking (I averaged 0.9-0.95 -g's braking) made the car feel MUCH more controlled, and I was able to modulate the brakes much better and also trail brake with more control.

Body roll was significantly reduced as well, which helped a lot with turn in and transitions between corners. The negative camber I got through lowering partially helped this as well, so I can't state that all benefits are a result of the springs/shocks/mounts upgrade.

I can definitely see adjustable shocks/struts in my future though. While the STR.T's pair very well with the SR springs, the car overall was not quite "loose" enough for me. I'd like a touch stiffer in the rear to help induce a touch more oversteer, and in general allow me to tune the suspension a bit more. I'm definitely no pro driver, but I know the car well and turned some reasonably quick times, and I can definitely see some room for improvement through fine tuning of the car

For the data-oriented folks out there, I pulled over 1.1 lateral g's (highest was 1.14) compared with a max of 1.04g's at my last track outing in a very similar corner (compression zone mid-corner on a RH turn). Can't state that is a result of the suspension as the 1.14 was at a track I know much better, but I do feel the suspension setup helped contribute to the higher cornering capabilities of the car.

Lastly, the car settled much better over knolls (which LRP has a really "nasty" uphill knoll over which the car gets VERY light), and that helped let me put the power down more quickly and feel confident that the car wouldn't try to step out much during the few times I was not perfectly straight over the top of the uphill

Hope this helps a few people who are curious about suspension upgrades on the Mustang. It makes a great difference especially when pushing the car to driver limits. I wouldn't say I've pushed my car to the car's limits yet, but I've hit my own current limits. Time for more track time

 

Comparison photos

OEM suspension:



New suspension

 

Obviously not the same corners, but for reference of car height and body roll, I think the difference is pretty apparent.

 

Thanks for sharing your experience!
I have recently changed my suspension using the similar components. I have only been driving the car on the back roads and pushing it a little. The car handles a lot better than stock. But your story and pictures, make me want to take the car to the track... There is one fairly close by: Laguna Seca...

 

I'm running BMR springs and Koni STR.T's. I love the combo. Ride is near factory and handling is much more planted and controlled.

Definitely a great bang for your buck upgrade.

 

Now that you steeped on the right direction, you should try better tires like the Michelin Pilot Super Sport. Better yet, try wider 18's wheels and tires, some adjustable swaybars, and on the future try watts links that will give a close to IRS driving feeling.
By the way, how good were those Recaro seats to keep you in place while taking those high speed curves?

 

I have a set of track wheels and tires. 18" GT500 OEM wheels. I purposely put on a harder compound tire to extract more track time out of one set of tires at the expense of slightly lower lap times. I am currently running 255's up front, 275's in the rear. When I eventually wear through the current tires, I'm most likely going with a square 275 setup using Nitto NT01's.

Definitely have my eye on the watts link too, although before that I'm going for a roll bar and 6-point harnesses.

The Recaro's are a very good seat. They fit me perfectly and offer very good lateral support. I am extremely happy with them. They are definitely not race seats, but I drive my car ~6000 street miles and probably ~1000-1500 track miles per year, so they were a good compromise and should be all I need for years to come when paired with a good harness setup!

Anyways a bit off topic - very happy with the setup so far. Should keep me happy for a couple years before going with adjustable shocks/struts and probably stiffer springs.

 

At this time I have the squared 275/40R19 Michelin Super Sport mounted on the stock brembo package wheels (9X19), also with KONI STRT & STEEDA Sport Springs, and GT500 strut mounts. Just installed my STRANO Adjustable sway bars, next on my list, I will like to get a squared set up for the track: 18X10 wheels and 285 wide tires. And after that probably get my watts link.

 

Thanks for the great review. The components you installed are an awesome combination.
If i had a coupe i'd be on that setup too probably.

 

The supersports are excellent tires from what everyone tells me. A friend Steve was just running them 2 weeks ago at Limerock with me. You like the square setup?

Any comparisons with/without the sways after the suspension? I am very impressed with the level of grip I'm getting out of the car with my current setup, but I might want/need stiffer sways when I go with R-compound tires I suppose.. but it corners pretty flat with the springs/struts/shocks & new mounts... much more flat than OEM!

I actually opted to get a car trailer over the winter instead of put the money into the car itself, so the rest of the modifications will wait a bit. It's a huge convenience (and peace of mind) to tow the car to track days now. Well worth the money in my opinion. But that $2500 would have funded pretty much everything else I wanted (short term) in the car. Need to get that big raise

Where do you take your car out to for tracks?

 

Did you experience any tripoding as a result of less travel or did all 4 tires stay planted in high - g corners?

 

HI:
<I just installed my Strano adjustable swaybars both in the midle hole, but probably I will reduce the stiffness from the rear sway bar to compare, fills very light on the rear at this time.>]
<Yes definitive, my 275/40R19 squared set up provides a very neutral handling feel>
< I used to track my prior '02 Porsche Carrera 911 in the local PCA track (a private airport). Right now I'm preparing my 5.0 to give a fight to those Porsches.>

 

Great pics. My car was very similar before / after. Suspension & brakes are the best upgrades for these GTs, IMO. Enjoy those beautiful East-Coast tracks!

 

Seemed very planted which is why I am not currently lookin at doing sways. A guy in an E36 M3 ran a session evenly matched with me and he captured a bunch of video footage chasing me - in that the Mustang seems to stay very planted, which backs up how the car felt. I will try to post that video here for anyone interested.

 

Nice - I'm amazed at what the mustang can do with fairly minimal modifications. Hope to see se video footage once you get yours out there

 

Super good info. A friend of mine has BMR springs/Koni yellows/BMR UCA LCA. He recently went to the ring for the first time and is now upgrading some stuff. LOL.

 

Haha I know that feeling...

 

Hi dmichaels, also I answered your other questions, they are attached to your message.
Enjoy your mustang!

 

For anyone who is interested, the below video was shot from an E36 M3 who ended up being very closely matched with me at a recent track day. Video posted to show my car's handling from an exterior shot.

 

Man you where doing great, with just few mods in your 5.0. The BMW was having trouble keeping up with you, at least was good for him to make a rear video of your GT in action . Get those adjustable sway bars & wider wheels and tires.