I have a 04 1500 5.3L auto/trans & I want to pur Flowmaster CAT back on. I only have so much to play with & is there any HP differance between the single pipe VS the dual out of the muffler? I know the sound is better. Can I get some help. I have a K&N CAI on there know. I would love a real duel exhaust but not enough dollars for that.