MikeNH, where'd you get your Tarmacs? I was looking at Tarmacs or SDX so I don't have to bother with centering rings, but then found a link on here to XXR 522s for around 100 less delivered. The Tarmac spokes look like they could be a bit more structurally supportive of the wheel when hitting the great Chicago winter potholes, but it's hard to tell from pictures.
Are you guys reusing factory lug nuts, or do you really need to get another set?
The other option I had been leaning to was just putting winter tires on the factory rims and getting a summer set of wheels. Tough to decide between that or running 17s for winter and factory summer for now. Getting 17s would at least save me swapping the factory tires off the rims and paying to remount them on another set.