Just bought a 09 LTZ last week and have under 200 miles when the front brakes started making grinding noises but only intermittently. I took it back to the Dealer today and they were really surprised at how bad it was after a test drive. The tech took booth front pads off and everything looked ok and no rotor groves. They found a new TSB that just came out May 1,2009. that described the issue. It will not make a noise on initial start up but as the brakes get hot as in stop and go driving they get worse. This is exactly what my problem was. The TSB says to put on new front brake pads and not turn the rotors. We compared the new pads to the old ones and there is quite a difference. They are now replaced and so far so good! Just wanted to give everybody a heads up on this problem.