The way i modified them was on the 155's if you look down in them, there is a metal flap that directs the exhaust through the baffle. I pried the flap open half way so i still get the back pressure but it is loud as heck. The only things that hold the pipe on is the muffler clamp itself. I ve had mine on for a year just about with no issues yet(knock on wood). In my poinion the 152's are nicer than the 155. 152's are about 4-5 inches longer and i like the turnouts. Good luck with them, in my opinion you cant go wrong for the $$$.
