I dont know of any diagrams but the stock pipes on my 04 TBA had a mesh with fiberglass in it covering the inside walls of the pipes and 4 baffles which are the walls with a pipe going through it. and at the very front of the pipe there is a reducer or something like it that brings the 1 3/4 inch pipe down to a 1 inch hole. It gradually does this within a few inches. Dont remove that. My pipes with 4 baffles removed, if u look through the front of the pipe towards the back you shouldnt see anything else than the one inch reducer just at the front.
