A while back I bought the H&R springs for the M coupe. They claim to lower 1.5 inches, however (not that I'm complaining), it only lowered it by 7/8th of an inch. I have ordered some bilsteins from Bavarian Auto, and they should be here in a couple of weeks. Those parts are not listed on Bilsteins USA website, but I found them on Bilsteins German site.
part numbers;
Front Left: VE3-E166
Front right: VE3-E167
Rears: BE3-E168
All together it cost $709.80. I cant wait to get them