Originally Posted by Munit
Considering normal m3's with a catless/HFC exhaust and an air filter make 375whp, I do not think a 4.4 L bored out factor motor is making the same power even with its cat's in place.
Comparing it to normal m3 does nothing for the comparison. All because it has a larger bore/stroke doesn't mean more hp. It will have more torque. Simple 15pct drivetrain loss puts the 4.4 motor at 378 whp.. The car has only 24 more hp at the crank which is approx 20whp...something you won't notice on the street. What you will feel is the additional torque provided by the 4.4 over the 4.0. Loose the cats on this motor and yes... It's over 400whp