Wheel gap will depend on the size of the sidewall. You could run a truck tire like a 255/70/18 and have no gap left (will handle like a truck too)What would 18's do to my forester on stock springs? Would I loose any of the wheel gap, gain any handling? Would my speedometer be off and what would happen to gas mileage? Anything else that I may missed let me know good or bad. Thanks.