my boss has a new BMW M5 that i wish i had. He just got it and beats on it all the time. He started it up tonight and it sounded like a diesel engine! sounded like valves were tapping and the fan hitting the shroud. It was weird. He said it is normal and when he reved the engine the sound disapated. I think there is something wrong. Does anyone know if its suppose to sound like that. I know the car has to break in and he beat it from day 1.