My 17" wheels have a 40mm offset, and there's isn't any fitment problem. Stock offset is 45mm btw. Super S is right, 17 vs 18 is more of personal preference, but remember, 18's are more than likely heavier than 17's, especially when you slap on tires.

Let's see, some other inexpensive lightweight wheels would be Kosei K1's, RH Evolution CP8's, Velox PG-5's.. er... here's a better list. http://www.wheelweights.net