Clutch vibration/grind

This is posted in the LT1 Tech area, but haven't gotten any help; thought I would try here...

I am having a problem with non-normal grinding going into first gear. It is pretty loud. Usually only happens after the car gets warm but not all the time. Also having an issue with a good vibration at anything above 3k RPM. If the car is neutral (M6) and the clutch is to the floor, I can rev all I want with no vibration. As soon as I let the clutch up (still in neutral) and rev above 3k rpm the vibration is there. Vibrations are there while driving also. Oh and I have no clutch slippage. None. Any help or information on this would be great. Thanks, Josh

Went to a shop today and they said that most likely I have the throw out bearing going of I have some fingers on the clutch that are bent. They recommended just replacing clutch and all while it was torn down. The said if I brought in my own parts labor to install the clutch would run about $300. How does this price sound???