the muffler is going to be the thing that changes your exhaust note more dramaticly then anything else. the gains you`ll see from just the headers and down pipe will be minimal (my opinion, i sure if i`m wrong someone will tell me). but they will look nice. a full cb will show more results, obviously, however you lose the stock sound. find a nice system and you should have a good sound, wal-mart brand muffler is going to give you the shitty sound.