In case people saw my old post I deleted, I'm back home now so I can type things out better. Anyways, I've owned Eibach Springs, H&R Springs, RDsport Springs, Ground Control Coil Conversion, KW V3, KW Clubsport, JRZ RS, and JRZ RS Pro. Out of those, I've tried the Eibachs, the KW's, and the JRZ's on the track. I've also had ride-alongs with those with Dinan spring and Ground Control and Moton setups. And of course, I have a good idea about the prices on all of these, and all of these setups were experienced on E90 or E92 M3's.
Anyways, I hope you guys have fun discussing this topic.