Besides changing the headers, ( which I don't think I'll do anytime soon), I was looking for a way to improve the exhaust a little bit. I was looking at a Flowmaster 50 series muffler. My question is,is changing the muffler good enough or should I get a whole new catback system? I figured the most resistance would be in the muffler and not simply the piping leading to the muffler. What do ya'll think?