It will look fine, but please don't even think about putting that skinny of a tire on the rear
on an 8.5" rim, a 255 or 265 series would be good. I have 265/50's on my 7.5" wheels and they dont stick out bad at all, so I'd think the same thing on an 8.5" wheel would look great.
If you want an even meaner look, go for some 275/50 BFG drag radials in the rear.