I swapped a 330d Touring xDrive for a RWD M235i - we take our car to the Alps for skiing (us, not the car) a couple of times each year. I had the exact same concern as you, but in the UK, we don't get M-Lites in xDrive format, so had to bite the bullet and live with RWD.
To date, I've driven the M235i in snow, slush and some steep standing-starts in the snow and not needed to resort to chains. So I'm quite pleased.
It's shod with snow-biased Pirelli Winter Sottozero S3 tyres. The previous car had the more performance-biased Sottozero Serie-II but I decided to trade a bit of wet handling for better snow performance on the S3. It is noisier than the S-II and doesn't quite handle as well in warmer, non-snow conditions, but I'm OK with that. You can see how the tread pattern is pretty 'chunky' for a performance winter:
And I did the recommended 'square' setup of 7.5J x 17 all-'round with 225/45 R 17 94V XL, I have also been impressed by how good these tyres have been in heavy rain and standing water. I never seem to get traction control engaging.