What would be the ideal wheel backspacing for my 4cyl '86 4Runner? I want a wider stance without stuffing the wheels into the edges of the wheel wells. Would 3.5" be good? Also, on a side note, would 31" tires ruin the little power that I have on the road? Or could I even go a little bit larger, say a 32"? The size on there now is 225, just about 29". Thanks for the help.

-J