[timhatimay]

I had cool carbons for about 35k miles and never had a problem. When I did them, I replaced the front rotors, but did not replace the rear. Occasionally in cold weather, there would be some minor squeal, but it was less squeal than the oem stock pads.

Sounds like an install issue, as grinding does not seem normal. The rears are so easy to install, why not just take the wheel off and check? The clunking sounds like maybe the backing plates and shims weren't used properly (or at all). That would make them clunk sometimes when changing directions (forward to reverse or reverse to forward), because there is some play in the pad.

Tim