I just drove the all seasons in 2-3 inches of snow in CT.
I have a RWD 335i.
Keep the car in Eco Pro mode, drive the speed limit, and you'll be fine.
With that said, I bought snow tires because it snows like a bitch here.
2012 335i Mineral Gray
Enzo 400R+|M Performance Exhaust/Brakes/Suspension/LSD|Bav Stage 1||ER CP/IC/DP | Dinan CAI |BMWF30.com