Even if it were an option, I'd rather go with Audi for quattro than BMW xdrive.
I also don't understand all of the comments saying "I would have bought an M3 if it were AWD..." because of snow. Give me a break. I've driven M3s now for 8 winters and regularly take my current M3 through snow storms and up into the mountains here to go skiing. Good aggressive snows are all you need, and you don't give up the great balance and RWD attitude that the M3 offers over AWD cars. Compromising and buying a car for the 2-3 weeks out of 52 where there may be a lot of snow on the ground is nonsense.
08 E90 | Jet Black / Black | 6MT
Mods: RAC RG63 w/ Pirelli Corsa 255F/285R | Akrapovic Evo Exhaust | OEM Blacklines
Winter Setup: OEM 18s w/ Nokian Hakkapeliita R 245/40-18