No cats and headers get you some nasty rasp... I do have this and cant seem to get rid of rasp... I'm on my 3rd catback now and still raspy...

 

My buddy has had both on his car and the SLP dual/dual was definately quieter than his Corsa. He is running FLPs w/ cats and Corsa and it is loud still. Not as loud as some other combos though. Nineball used to run the dual/dual and it was very "stealthy".