If you move the rear bump stops in on the frame you can get another inch of rim under there in the rear, not sure what your ideas are. I am trying to keep the tires in the wheel well while getting as much tire as possible.
The factory backspacing is about 3.5 om a 5 inch wide rim...
I will be using 4.5 backspacing on an 8 inch rim...
so, 1 inch further under the car and 2 inches to fill the wheel well outwards.
In the front I plan on 4 inch backspacing on a 7 inch rim...should fit nicely...
Here are the rims I will be using, they build the rims to order so there is no guessing.
Motegi mr224
http://www.ultimatewheeltire.com/index. ... mr224.html