Originally Posted by E90330iS
So it is not because of the more restrictive Catalyst Converter for the U.S. Spec models?? I thought that was the case for E46 M3s.
That is also a possibility. I was just pointing out the DIN hp has always been more than SAE hp. As of about 2005 the SAE test standard is more conservative, so this would further widen the difference -- in addition to any restrictive US emissions h/w.