I feel a bit silly about posting this, but at the same time just excited enough to post it anyway.
So yeah, after being frustrated by limited Z4 use due to way too much snow last year, I have gone ahead and ordered a set of used BMW rims (in nice condition) with brand new Bridgestone Blizzak Revo 2 tires on 'em.
The rims are plain old star spoke 200s, and I'm dropping down an inch from 18" for my regulars to 17" for the winters. That ought to keep me on the road, which of course is the point. Quite happy about that.
So there, now I've gone and made a knob of myself by crowing about having bought a set of winter tires. So be it.
The 3.0 E85 Z4 is the only car I've got stuck in snow, the Bridgestone RFT's and open diff meant it was laughably bad at finding grip to get going should you stop. Also managed to slide backwards down a hill I was crawling up in 1st gear - very lucky nobody was behind