Most of the good tire shops have a "store-bought" device like I rigged up, to verify rim and tire fit. With 18X8's you would be wise to check everything out locally. Another factor to figure in is how much you've dropped the suspension.
I had hoped to get some rims that I liked with a 3-1/2 BS but I just couldn't get what I wanted in that configuration. Isn"t that the way it goes? Good luck with your hunt!!!
Dave
