now the rims are :

18x9.5 rear +35 offset

18x8.5 front +35 offset

car is a 93 s13 convertible

 

my main thing is finding out what size for the fronts...

 

Square: 235f, 255r.
Stretch: 215f, 235r.
adjust aspect ratio to suite a ~25" tall tire.

*edit* this guy has 17x8.5+30 with 235, and 17x9.5+43 with 255. It's not an 18", but you get the idea. Pretty square.

http://www.stillensucks.com/Project_.../photos/17.jpg

 

i'm dumb, you mean like 215x25x18 f and 235x25x18 r?

 

If you want the narrow ones, then 215/40/18 front, and 235/35/18 or 235/40/18 rear. The 40 series rear will give you more of a raked look (larger in rear).

You may want to run a 10mm spacer up front for a more even (flushness) look, too.