What Ed (jonesin) and Ryan... said.
I live in Rochester, NY and I would recommend a set of even used snow tires instead of new all seasons.
I have ASC and limited slip and I have no problems in the snow.
1995 325i, 225K miles (yes!), 5sp, LSD, M3 cat back, halo projectors, H&R/Bilstein/etc. suspension overhaul, painted sideskirts...