I've installed 3 of SPEC's stage 3 clutch in my own car. At first they would work properly and then, just as you described Josh, the clutch would not fully disengage with the pedal fully depressed. The first time this happened, I replaced EVERYTHING including the clutch pedal, master cylinder, slave cylinder, all lines, clutch fork, throw-out bearing, etc. Literally everything. The problem was the clutch. Put in another SPEC stage 3 and few months later it started happening again. Also happened a third time. There's definetely a flaw in the pressure plate design. I said fuck it and installed a Clutch Masters stage 4 and haven't had a single problem since. I recently had a guy bring me his car for repair because his clutch was doing the same thing to him. Turned out to be a SPEC stage 3. Replaced that with a CM stage 4 also and everything's been great. These 420A/NVT350 SPEC clutches are very notorious for this problem, as SPEC knows it.