My 330i ZHP was completely USELESS in the snow - even with DSC. Then I bought 17" Bridgestone Blizzak WS-50's and a set of winter rims. Now I can run with the trucks and SUV. If you've never experienced great snow tires on a BMW, you wouldn't believe tires would make THAT much of a difference. I didn't believe it either. It is AWESOME.
I imagine the E92 M3 is going to require a little more finesse, but with DSC and a gentle foot, WITH some Blizzaks, I'll get by ok for a few months during snow. They don't
sport-perform too well on the dry stuff, but I can put up with it.
