Ground control bmw e9x complete street/sport kit

[ConceptE92]

Hello BimmerPost Family!

I have done some searching and have tried to contact Ground Control themselves, however, I cannot get a solid answer almost by no one with some solid explanation.

I have previously owned a 2012 E92 M3 with the coilover conversion kit from GC, however, now I am looking to purchase the Complete Street Kit for a different 2011 E92 M3 that I own. Having said that, I am looking to find out the spring rate that some of you have ran that have owned this kit.

I previously lived in FL where the roads were pretty flat, and I believe at the time I ran a 400F/700R spring rate on the conversion kit which was perfectly fine, nothing to worry about. I took the car to the track about 4-5 times a year around Homestead MotorSpeedway and Palm Beach and no complaints, note that the again the flat surface didn't bother.

Now that I live in GA, I have done some track days here at Road Atlanta with my E46 M3. On this particular car the Spring Rates are 600/900 and the car feels great, however, this car is a lot lighter (3,100 lbs) vs the E92 M3.

It has been 5 years since I have owned the conversion kit on my 2012 E92 M3 which I no longer own, so what I remember may have felt fine back then, however, I am looking to get the right kit w the right spring rates around this time.

What do you recommend?
What spring rates do you run at Road Atlanta and other tracks that have more elevation change to them?
I understand that higher spring rates doesn't necessary improve grip, matter of fact opposite in extreme cases depending on pavement, however, I am trying to dial in the correct numbers. In terms of tires, I am running RE71 as the tire, 275/35/18.

Please let me know what you recommend and what your experience has been. I am also open to other suspension setup, however, I do have a budget I would like to stick of $2K.

Looking forward to your response,

Thank you,


AR