i've edited this question because i suspect it wasn't clear hence why nobody replied to it.

i completely understand that this mod changes (improves) the exhaust sound.

what i'm wondering is why not just have two parallel pipes? what does the fact that the exhaust joins and then splits again do? i'm not referring to straight pipes that have no mufflers.

i could just get an exhaust shop to put in two pipes whereas i'd have to get the X piece from the US.

thanks in advance!