I had a shake problem using a SPEC Stage 3 Clutch AND a Centerforce clutch in the early days. One shook at idle, the other shook between 3500 and 4000rpm. My problem was that I assumed the aftermarket clutch centered itself to the Crankshaft and Flexplate in the same way the OEM clutch did.

I jacked the car up, opened the inspection plate on the transmission and measured the distance between the flex plate teeth and the flywheel at each of the four bolt locations. The clutch was indeed bolted down slightly off center. Got everything centered up within 20 minutes and it was smooth sailing after that.

As for the chatter and rattling, thats just par for the course. I haven't met anyone with a Stage 3 clutch that didn't make some sort of noise at idle.

If things have changed in the last two years, by all means update me. I'd love a Stage 3, quite, 6 puck, sprung disc with hulk strength pressure plate, but light weight clutch pedal feel :) Santa?