I agree that the c5z would destroy an m3 on track, straights, and under the sheets
but that's in the hands of a good driver, otherwise the c5z is much harder to drive to the limits then the m3, which is what makes the m3 so appealing. And your statement about beating c5z has too many variables. I've passed many c6z's and a 458 in my z4m. Certainly doesn't mean the z4m is quicker than those stated cars.