95 Formula: Wheel Size?

I have a 95 formula with 16 inch stock wheels. The wheel's painted finish is gone/tires are worn out and I want to buy new ones, probably 17's to make room for bigger brakes, and wider rims (at least in the rear) for more traction. The wheels for sale like on e-bay are listed in various inch widths, such as 9.5, 11, etc. Does anyone know how wide my 16's probably are, and how wide I can go without looking stupid or having steering/rub problems? The tire size is currently 245/50 ZR 16. I see some ZR-1 combo packages that sound good, with 9.5 fronts and 11 inch rears (50 mm offset), but I don't want to end up with 2 inches of rubber sticking out the sides of the car. Opinions/sources please?