whats size rims?and offset

[raw122]

i have been looking at vette rims but looks like they have differnt offsets unless someone know a set that dont.i am going to get 17 or 18's aftermarket but what offset and how wide do i need to get,does the rims have to have a different offset or if i get them the same will it stick out the same distance aways from car

[mrr23]

they have different sizes front to rear. here's some C5 and C6 wheels on my cars

http://www.ls1.com/forums/showthread...89#post1049789