In these cases, why not go for the tire 'socks' then? Never used them, but simple concept alone makes me think they'd work better and would take a comparable amount of time to install/uninstall on bad weather days as this spray would.
The other option is cheap used BMW wheels/winters. It's not too hard to find $3-400 sets on CL and the like, it's still spending money but not $500 wheels, $900 new tires and $200 TPMS sensors. (I run ugly ass OE steelies with like new used tires and no TPMS, which I grabbed from a fellow BMW fanatic for $320).