And how did it work out for the Buggy World guys? IE: no circle leading up to the exhaust. Good? Bad? I'm assuming bad or you would not have brought it up. OK............so I'm going to over analyze it with what little knowledge I have of exhaust technology. But it seems that backpressure is created by the muffler while evening out the flow and creating better scavenging from the cylinders is caused by the tube leading up to the muffler.

Right? Wrong? I could understand needing the circle part for even flow and scavenging. But to add back pressure???? Not sure I see that one.

Just thinking out loud. Please steer me if you are more knowledgable (which wouldn't take much in this case).