Benefits of an X-pipe vs straight pipes?

[splash_o'_yelow]

what you were seeing with the rag was the normal valve overlap of the valvetrain. it causes scavenging and cooling of the top of the piston. of course you wouldnt see the rags oving at the same time, to balance power and lessen vibrations one side of the motor fires then the other. also the exhaust pulses because it dosent have a constant flow. the x pipe will help with evening out youre back pressure and help it flow better. the cats that are in line one behind the other are two different types of cat. one has one type of catalyst in it and the other another one. reduces emissions two different ways. one removes NOx and the other hydrocarbons. hope this helps you to understand a little better whats going on.