Hmm...
You're saying a car that is known for it's handling abilities cannot handle.
The Porsche should handle better, it's only say... anywhere from 20-50k more expensive depending on what 911 your daddy owns. My opinion is based off test driving the vehicle compared with Porsches, Vettes, Supras, and any other top end car. Hell, I've ridden in a 355 and 360 Modena, and even a Diablo. The M3 is not the best car on the market, but it is a damn nice sports car and handles exceptionally well.
I can say this though, a car handles exactly how the owners drive it. If you're driving a M3, and you say it can't handle, it obviously has a defect or the owner doesn't know how to drive. Period.