I'm looking at buying a 2003 540i Sport 6 speed with 18" M wheels. It has a new set of Pirelli all season 35 profile tires (can't remember the specific model). Anyone have experience with "all season" tires in this size in the snow? I'm wondering if I need a set of snow tires here in Minnesota, or if I can get by with the current tires year-round. The 2002 325cic stays snug in the garage in the winter.