hey guys. i was just curious. i've heard most exhaust pipe would fit along with one another. but umm.. whats the diffrence between. a 86-88na.. 86-88t11.. 89-91na and a 89-91t11..?? and is the pipe size all the same.? or is it just the turbo that is a bit larger.? so do you guys know.. thanks..

aka_rocket