So, what I want to do is avoid the high cost of buying 4 new winter tires that match the orig. equipment on my daughter's GXP. She's running 18 x 8's (245 & 225's) and I want to drop down to a smaller wheel size, like 245 x 17 or even a 16.I can get all 4 at Costco for a heckuva lot less and still buy 4 steel wheels to fit. Any Grand Prix owners out there with a better idea? It's only city driving in S. Ontario by the way!