I can tell you that there is no way in hell I am buying the new m3 unless it has 450 horsepower at the very LEAST. Sorry 400 or 415 just does not cut it when everyone is going bigger.
Sadly the only choices for a high strung NA motor is becoming porsche, audi and ferrari and lambo of course.
Ill just jump into an R8 v10 when the next gen comes out. 400 hp m3 will simply get slaughtered by teh competition