I live in Colorado and my 650i has been and still is my only driver. For the last three years I had a 2006 650i on which I had an extra set of 18" BMW wheels with four Dunlops Winter Sports M3 Run flats 245/45R 18. The car worked great in the Denver-Boulder area and in the mountains when I went skiing. This year, and in a few weeks, I'll put the same wheels with new Dunlop tires for this winter season on my 2010 650i. I expect the same performance as with the 2006. One caution is the snow tires are not as effective on dry roads as the summer tires so the back end will want to drift a little and most importantly if you have a heavy foot the rear tires will wear at an alarmingly quick rate.