I had a professional shop install a Spec II for me. About 30,000 miles later, the clutch would not disengage, like the orignal poster had said. I pulled it apart and two PP bolts were loose, one was only FINGER TIGHT!!!!! The Disc still had lots of life left.

I put it all back together with a LS6 clutch(reliability), some Red Loctitie on the PP bolts and it works great!!!