I went the beater route...although I wouldn't exactly all mt TT a beater. I use it for my daily commute, which is only 5km each way. I figured I was doing more harm than good driving the M3 to work since the engine wasn't even warm by the time I got to work.
Also, the TT is AWD which is an advantage when it snows. My M3 is a weekend car that will be making some side trips to the Nurburgring.