I can help here.. you need to start with what your wheels currently are (width and offset). If you are looking to not change your wheel width, then you can base all offset off of that. If you change the width, your offset also will be affected.huh?
you have 215's?! no wonder why your rubbing o_o.thank you Throwdown..
My tires are 215/40/17
Wheels are ET 35 offset and 7.5
The tires rub...
So I decided to hammer the inside of the fenders to prevent the rubbing. (is "rub" is the correct word ?)
I'll take photos to show, it'll be done tomorrow...