Good points re xDrive.I just sold an M3, actually. I really did like the 4 series... I was skeptical at first, but the name/series change makes sense in the long run.
I prefer RWD for a "fun car", which this would be if I were to purchase one, but there is no argument that the XDrive is a better option for everyday if you live in a snowy/wet climate. I've lived in Vermont and Colorado both and would go with XDrive if I were there. Otherwise, the babysitter technology will do an amazing job of keeping you safe when weather turns a bit bad and being able to tone them down is part of driving an enthusiast car.