I finally got my Koni Sport dampers and 2011 M Sport springs installed. Wow what a difference! The car now has very little lift and squat compared with my stock 2009 M Sport suspension and the ride feels better than the OEM set up. Just shows how bad the stock dampers are.
First some background. I wanted to improve my car's handling without lowering it since I have Alufelgen SF-71 19" wheels. I like the stance of the car with the wheels and I didn't want to have any rubbing issues. I also have rolled fenders because I previsously had some rubbing issues with more than one person in the car because of the soft OEM rear springs. I was looking to improve performance on the street without sacrificing ride quality. I have no plans to track or autocross my car. My car also has the E93 M3 28mm sway bar and the M3control arm/tension rod kit which were installed before the new dampers and springs. So my set up now consists of:
E93 M3 FSB and Bushings
M3 Control Arms/Tension Rods
Koni Sport Adjustable Dampers (with external front and rear adjustment)
2011 M Sport Springs
Since I was not able to find any aftermarket springs that didn't lower the car at least a half inch (and coilovers weren't the way I wanted to go) I decided to investigate the 2011 and later OEM M Sport springs when I found out that BMW had increased the spring rates and changed the springs from progressive to linear beginning on the 2011 model.
http://www.bimmer-mag.com/issues/96/...-better?page=2 I was lucky enough to pick up a set of 2011 M Sport springs from a forum member who had swapped out his springs for aftermarket springs. I decided to pair the springs with Koni Sport adjustable dampers. I also considered Koni FSDs because because of their good ride quality, but ultimately decided that the adjustablity of the Koni Sports was more important to me. I purchsed the Koni dampers from Harold at HPA. Harold has been a great resource in helping make my decisons. He also has the Koni Sport dampers available with external rear adjustment. I have't seen them available through any other vendor with that feature.
The big question is how much of the improvement in my car is due the Koni Sport dampers and how much is due to the 2011 M Sport springs. There is no way for me to know since they were installed at the same time. All I can say is that if you already have the 2011/12 M Sport springs that the Koni Sport dampers, M3 FSB and control arms/tension rods make for a great set up. If you don't have 2011/12 M Sport springs and you want to maintain a stock ride height they are worth considering if you can find a set along with a good set of aftermarket dampers.