unless your boots are torn or you hear a clicking noise while turning either way your cv shafts should be ok, they usually give a vibe, or a clicking while turning if bad, i'm running the same clutch, street / strip disk on my ls,(see your other posting)and have something similar on occasions but i think mine is either the rubber in the clutch pedal mount or in the rod/adj on clutch master cyl. i hear mine while depressing the clutch on occasion, which could be related to the clutch pedal pressure difference