I recently got a Apexi muffler. I put it on two days ago it sounds awesome but i want to gain atleast a couple of horsepower. Can you turn that into a catback or will i spend more doing that? My friend said I should go with 3 inch piping instead of 2 inch. But i asked around and some said you will gain hprsepower and some said i would lose horsepower. Can anyone give me some advice?