Sounds exactly like mine did from what I can tell. Don't know how many miles your car has - mine had 21,000. I took mine apart and it was the pilot bushing. TO bearing was fine, clutch disc was fine, I had Jim Jandik at Powertorque Systems look at TO and resurface clutch plate. I cleaned up flywheel in the car with Scotchbrite. The ONLY thing I replaced was the pilot bushing - with one of the fluted ones. I added ZF Docs C-beam plates as well. No more noise and everything works great. Jim told me the factory TO bearing rarely goes bad - and a good used factory one is better then the reproductions made in China. So check it out...
http://www.zr1.net/forum/showthread.php?t=26185