The tune and the exhaust routing are both factors.
"The core of C63 is the 6208 cc DOHC 32-valve V8. It is not derived from any production engines of Mercedes-Benz, but designed and developed entirely by the AMG division. This engine has been used in various AMG models, namely E63, CLS63, CLK63, S63, ML63 and CL63. The baby C63 is the last one to call its service. Naturally, installed in the tighter engine compartment resulted in somewhat compromised exhaust routing. This mean some 57 horsepower has been lost compare with the larger E63 AMG. Still, the C63 cranks out 457 horsepower at 6800 rpm, some 37 horses more than the new M3. Moreover, its maximum torque of 443 lb-ft is a massive 148 lb-ft more than the BMW !"
Click the link:
Mercedes-Benz C-class W204
I also agree with tresean1. And, 2tonOfun, :thumbsup:. I miss some my forced induction cars.