I run the BMW 214's (the Y-spoke 20" wheels you are referring to) on Dunlop runflats in the summer and I have a set of factory 18" BMW wheels with all season bridgestone tires that are not run flats that I use in the winter. I drive the car 23 miles each way to and from work and don't really worry about the non runflat tires. My insurance offers free roadside assistance with my policy so I'll rely on that if I need service while driving. It's never a bad idea to take along a spare if you are going on a road trip and are outside major metropolitan areas though.