Any +1 or +2 wheel upgrade will increase rotating and unsprung mass. In turn this will put a higher load on the engine. For a big tire and wheel package, you will need to go with heavier supporting mods to start dropping pulley sizes. You will need headers, rockers or aftermarket cam, a bigger TB, CAI/FWI, and a ported SC will help too. At that point I'd start looking at the 3.4 with the wheels. Depending on your budget, you can skip all that by going right to a full-size IC with a smaller pulley on the SC; but the car won't be up to it's potential w/o the other supporting mods. A good full-size IC with a 3.3 or 3.2 pulley will probably add close to 50-60 WHP.