I would prefer 33's but yea most of the fender would have to be modded. But hey going from a stock 27 to a 31 inch tire aint bad.
If your tire is that close I to the Spring perch I will go ahead and remove mine before mounting the tires. I know the guys running 245/75/16 had to remove/cut theirs off as well as a 1.25 inch wheel spacer.
I may have to get some hubcentric.