My 2003 C32 makes a growling sound when I step on the accelerator around 2000 RPM. I can't tell if it is an engine, supercharger or exhaust issue. It goes away or gets lost in supercharger whine / engine noise past 3500 RPM or so. Anyone had this problem? I'm under warranty, just would like to know what to suggest they check when I take it in.

My car is doing it to. I had it looked at and they think it's low on oil. I'll find out later this afternoon. I think it is a cracked header or lifter.

could just be the clutch bearing on the supercharger. Dealer will want to charge you 2000 plus for the problem when all you need is a 20.00 bearing. If your in GA Ill fix it cheap.