Pre-gens had a 16x8 option (not so pretty, but very functional), Bullitt's 17x8s, Saleen's 17/18x8s, GXP's 18x8, research. There are alot of x8 wheels out there for our cars.
Biggest thing to make sure of is the central bore has to be big enough. most imports won't work because they run a smaller center bore and the wheel won't fit. Ford is one of few that have a bigger hub bore than our cars do. I believe the 350z's will work as well, but I don't think they have a x8 option, unless you get the stanced wheels and I think the offset is too much for our cars on those. Just food for thought.