audi's are awesome in the snow, but typically older BMW's have a rep for being terrible in the snow. The new ones are much better, still not quite as good as the audi's, but more than good enough. I haven't heard a ton about mercedes, and I'm pretty sure its RWD, but it does have ABS, and I have a friend who skis a ton and drives a 318ti all winter, and hes fine, so I would just say get some good snow tires and don't be stupid