The head pipes are CB550, which tuck in a little tighter to the frame rails. One of the pipes (#3 I believe) had to be cut and rewelded about halfway down the front run in order to turn out along the correct line. The megaphones are made from conventional 2-1/2" auto exhaust tubing, with a pie-shaped slice cut out along the entire length, in order to form the small end down to the headpipe diameter. The seam was mig-welded. There is a slight reverse cone at the outlet, and no baffles.