Does installing an X pipe really do anything? I have true duels all the way back from the cats and haven't had any problems. Would there be any benefits installing an X pipe?

The reason I am asking is because I am taking it in tomorrow to have two brand spanking new magniflow 14829s put on. I haven't decided if I want to get rid of the two rear resonators or not. I don't wan't loud.It sounds pretty good now with the stock mufflers on but there old (92) and I figure that the mags would let it breath easier. I was looking at the mags from end to end and they are true free flow.Nothing blocking anything in the middle.I don't know if the stocks are like that and what about the stock resonators? Do they block the flow?