yes it is possible. i know a guy running that combo with teh afs(?) o3 cobras w/ 335/30-18 on the back. he said clearancing and fender rolling was a necessity for them to fit
18x10.5 shouldnt be a problem on the rear.....a 335 tire would probably most definatly rub though....i run 275's on my 10.5's and its close to the quad shock....but if i flipped the quad i could DEF run a 315.....