Im going to chime in here and as for SPEC Clutches they get my vote over most other Clutches. SPEC Stage 3 = Great holding Power, No Chatter after proberly Broken in (500 Miles with lots of Stop and go and differnt Heat Cycles, No High RPM take offs). They will make your Tire Bit like crazy. The Clutch effort is good and not so Stiff after break in. My Properly broken in Spec Stage 3 wants to Walk through my Line Lock before Spinning the Tires for Burn Out, if released to fast. They Grip like Crazy. Ive heard guys say they are No Good but its like most things in life that are Man Made, you may come across one from time to time that was overlooked at the production plant. But I know they are Realy good I have had great sucess with mine in my Mustang. Other companies that get my vote also would be RAM / Centerforce. Those Cheap Chit you see on ebay like F1 etc they are complete garbage, trust me i know, had one didnt last a week without burning/sliping during the time of the breakin, followed the same steps with my Spec and Ram Clutches with no Problems and great performance and life.
I never had the issues with chattering or failures either. Every SPEC clutch I've ever had worked excellent and held up great. No chatter, great holding power. I did change my clutch disc to a Pro-motion hybrid disc to help my trans live longer but I'm using the same SPEC III pressure plate.
my girlfriend bought her 94 GT with a spec in it. i hated it. very all or nothing. very stiff. not a street clutch imo.
my 95 GT had a centerforce II. i highly reccommend. light pedal effort and smooth engagement. very streetable.
also reccommend doing the maximum motorsport package that includes their clutch cable ( best aftermarket cable out there ), firewall adjuster and quadrant. its $127.68 well spent.