You must have had the TCS off then. BMWs stick to the road like glue. 
With decent snows you’ll be fine in the snow with RWD. Just don’t try to drive out of a plowed in driveway and don’t take it out if there’s 5 inches of snow or more on the roads. BMW had a stretch of almost 10 years without an AWD car. It never stopped people form driving them in the winter.