Originally Posted by baba louey
There must have been a weakness of some sort with the older set up for BMW to cease production of those parts. It sounds like the aftermarket have picked up where BMW left off.
I tend to agree with your comment that tracking is not particularly hard on the clutch unless one is 'speed' shifting all the time. One problem I had with my old RX7's clutch at the track was that it would get too hot and start to shudder when leaving the pits from a dead stop. A switch to an aftermarket disk/plate fixed that problem.
From what I heard, the decision to dump the '08 setup in favor of the bigger '09 option was derived primarily from owner complaints around noise from the setup - especially out of gear at idle and at low speed. Mine makes a little noise but, since I know why, its never really bothered me.
Not sure if you remember but back in '08 / '09, folks were getting fluid swaps in the tranny and diff because of noises. Either BMW got sick of fluid swaps under warranty or thought a bigger clutch/flywheel would make a real difference in performance and noise.