if my new long tube headers are 3" that convert to 2.5" to connect with the cats, what size muffler in and out do i need? im thinking about putting 2 4x14 round body magnaflows on there and right now i just have cat-back exhaust so im gonna need some tubing for the second muffler. what size tubing do i need to make it all work and where can i get it? i was also thinking about throwing an x-pipe in there as well