The SPEC Stage III is really an ON/OFF switch. The shuddering is due to the lack of its ability to slip/feather into gear. You did in fact pay extra for this. You bought a "Race" clutch, not OEM. I hate the clutch chatter, myself. When not in gear and the clutch is out, it chatters very loudly. It squeeks when engaging and makes racket all over. When you side-step that puppy at the line or when baning thru the gears, that is when you appreciate the SPEC. I suggest to get another OEM unless you are boosted or run at the track often. Otherwise your daily driver will drive you nuts.
