This is off a 029 super. I pried it open. one is before the other after. Definitely a difference You have to leave the square tube in on this type of muffler because it helps support the two haves as the studs pull in on the center. the tubes keep it from getting crushed. Exhaust flows in through the square tube and out the little holes and then fills up the chamber and out the little oblong holes in the front. It is very very restrictive when stock. I think, in this case especially because its so restricted when stock, it makes the saw run a little cooler when moded.