With my E90's I drove the summer performace tires in an inch of snow or less. Otherwise, just left it in the garage. I couldn't get past my driveway in more snow than that. Lately I found that I've gotta be on snowy roads more than I'd like to be so threw on the Blizzack tire/wheel package from Tire Rack. No sense risking injury or damage when it can all be prevented with $1200 worth of snow tires on all 4 corners.
2013 F30 335i | Sportline | Imperial Blue Metallic | Black Dakota | 6-speed | HK | Cold | Premium | 19" Staggered Sports | M-Performance Exhaust
2009 E90 335i
2007 E90 328xi