I'm looking to get new rims with all season tires. i found some rims but dont know the bolt pattern. I have an 07 ss/sc w/ stock 18s right now. Looking at the rims

http://www.xxrwheels.com/sportmax_508.shtml#
http://www.xxrwheels.com/xxr_520.shtml#

I do not know the sizes i should get. 17*7 or 18* 7.5 what are the differences and pros/cons between those two. and again all season tires would be going on them once i find some that preform well in the winter and summer.

thanks.