31" has a slight rub, but depending on what your going to use it for there is no sense in trimming the wheel well in the rear part of the fender well unless you tend to off-road it regularly. Also the mechanic who helps me is a professional off-road/rock crawler like Lord SUV, and Jants says wheel rub is not as big a deal as people make it out to be because eventually it will wear a pattern in the tire.
I currently ride 30" and have a 1.25" coil lift in the front and have plenty of room. I think it would work fine w/o the lift. I see lots of "E" with 30" tires that are daily drivers...keep us all posted and best of luck with whatever you choose to do.....