I went with the 18inch set of winter tire with replica rims, did that in my E93 with no issues. I get them from this very reputable place in Toronto so I trust their quality of rims. Last set of rim I had lasted 7 years of winter and no issues at all before I sold them. These tires are not low profile so they don't look too small. Tire is Bridgestone Blizzakk, so far so good. Not sure if I like the traction, I used to have the Continental ExtremeWinterContact and I loved it.
19 rim and tire is on another level in terms of pricing, just not worth it for couple months of beating in the salt.
I have the same MSport Rim as you have for the summer.
Never had any issues with non-run flat winter tires, worst case call road side assistance.