JustAnotherLS2

Noticed today, that when I rest my foot on the cluth pedal(NOT engaging the clutch, just resting my foot on the pedal), I get a vibration from the pedal. I revved it a bit, still with my foot resting on the clutch, and the vibration gets worse. The only other problem associated with this is, when I bring the car up to high RPM, like around 5000 RPM or higher, the clutch pedal gets really hard to engage, almost similar to a stage 3 or 4 Monster clutch or any aftermarket staged clutch for that matter, and it gives me a problem going into the next gear. Under normal driving conditions, theres no problem at all other than the vibration, that is RPM dependent. Clutch has about 15,000 miles on it. Its an OEM spec clutch. Car is a 2006 GTO, with 70,000 miles on it if that matters. Everything is stock except for LT headers, cat back, and K&N CAI.