I realize that this IS a Porsche forum, but c'mon give BMW some major kudos here. This engine is going to be very inspiring and will likely run with the 911S; I know not on the track, but trackies are the minority.
To say that the M3 will not be any faster than the 335 is crazy. And as far as the posts about engine reliabilty; look at how many 911 engines implode and/or have RMS issues.
Lastly, as far as the RS4 is concerned, I'm quite confident the M will out run it. (Less overall weight and less parasitic HP loss; not to mention a host of other go fast goodies that the M engineers utilize.)