BMW 325 i or xi for winter driving?

I'm considering getting a BMW 325, but I'm a little concerned about the rear wheel drive. I had a Mustang before and it was HORRIBLE in the snow. Basically a door stop until the driveway thawed out. Are BMWs better in winter weather? Or would I be better off going with the all-wheel drive xi? Is there that much of a difference? Thanks for your help!