My Solstice has developed a metallic "buzz" in the exhaust system when the car is first pulled out after it has sat for a period of time. I had the car to the dealer yesterday and they checked for loose hangers, brackets etc. The sales manager said that there is a bulletin out from GM about the buzz. The bulletin says not to replace anything at this time. The manager said that in his experience this means that GM is looking for a solution to the problem and will send out a new bulletin as soon as a fix is determined. After my initial pull out the buzz goes away. It sound very much like the sound I once had in a car that had a loose heat shield on the catalytic converter. It has not been a problem, I just thought I would pass on the info, expecially the part about GM looking for a solution. Happy driving!