Everything he said. I put them on 10.5" wheels which I think is as small as you want to go. Wider would be better but they look fine and seem to handle fine on the 10.5" wheels.I have 315/35/20 NT05's on mine, but on 20x11" Steeda Spyder wheels. 20x10's are almost too narrow for that tire per Nitto recommendations (they suggest 10.5-12" wide wheels).
I thought Godspeed Omegas were available in an 11" wide version? If so, they should have a 62-63 mm offset instead of 45 mm, otherwise they'll stick outside of the fenderwells.