I have:
18x8.5 +35
19x9.5 +35

The difficulty in the front is always the suspension bolt on top of the wheel. As you're planning to stay the same offset, you won't have any problem rubbing, just sticking outside the wheel well. In the rear, the space is gained by going to higher offsets. My +35 look absolutely stock, in terms of where they are placed in the wells. My guess is that they will house absolutely monster wheels, with the higher offset. People have put 305's on +35's.

Hope that helps.
Shawn