I agree if the CSL clutch is "wearing out", then its due to driver
abuse. The BMW 850CSL clutch is the "upgrade" for the E39 M5 and E52
Z8:

http://www.uucmotorwerks.com/flywheel/V8/index.htm

As the ad says, this clutch is setup to give "normal" lifespan
comparable to standard BMW models, 50K-80K miles depending on driving
style. If you're getting less mileage on your clutch than this, its
due to driver abuse.....