Hi Busso, I just picked up a generic muffler with an inlet large enough to slip over the pony exhaust outlet. My 3J has the exhaust pointing horizontally out the right/passenger side, and the 5U has the vertical outlet poking up through the hood. The muffler slips over both. I only use it when starting, otherwise I take it off and stow it. I don't clamp it on - just slip it over. Still makes a huge reduction in noise. I'd recommend any muffler you could get your hands on - prefer a muffler over a resonator (straight through) for max noise reduction. My muffler is about 15" long and about 10" diameter. Check with your local custom exhaust shop because they sometimes have take-offs lying around for $20 - that's where I got mine from. But looking online, Walmart's advertising a Walker 18150 for a Toyota Corolla that would probably work. Weld a handle on it so you can hold it without getting burned and you'd be golden for $50