the down side, if you were to run 9" comps on the front is the brake clearances, kind of why some go for 8.5 fronts, ive recently found this issue and its taken Martoon a hell of a lot of work to be able to make brakes of a decent size to fit.
i run 9" all round on R888 245/40/18's.
Mad Yum has 10" rears and never had big issues with clearances, but has now had the lower rear lips flared to make them slightly more accomodating - and hes running 8.5's up front.
another pic of Guido's, the tyres are stretched, and i never realised they were 10" as Mike has said.
and mine with the 9's.