Ground Control is good, but the shocks tend to need to be rebuilt fairly often.
Be careful with lowering a BMW. The front suspension geometry does not allow much lowering before the lower control arms are pointed the wrong way and cause some handling issues.
About 3/4" - 1" is about all that is safe without modified lower control arms.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)