Well there is been many many discussions about the RS4 not having all its quoted HP so maybe the explanation is that the M3 is getting the same issue and even less real hp than the RS4. This could explain why M3 times are not better.
This is also my main question mark : how the RS4 with 4wd (power loss) and 100kg (approx) heavier can have the same chronos ????
Well I personally do not focus on finding the reason I better enjoy the fact