i had 15 x 6.5 with only a little catch on the guards at the front with full lock if suspension fully depressed (and it was only just). got more catching with 14 x 5.5 and 185 60 r14's, have gone to 175 60 r14 and no problems.
It all depends on wheel offset and your car.
6.5 were very wide though on the 1200, made it tramline a bit, some guys are running 13 x 7inch so anyting is possible