Well, I guess you don't even need pipe or tubing. Could be anything that
bends easily. What about using ethafoam cylinders the right diameter.
Sorta like those floating things kids use in the pool, only smaller in
diameter. Shape the pieces and glue them together. Once you like the
shape, give each piece a coat of 4 oz fiberglass cloth, using your
favorite resin.
Maybe ABS plastic water pipe. Cut, notch and bend as needed, then
heat weld the joints. Add stiffeners as needed on the inside of bends
so they don't get in the way at the mufffler shop.

Pete Stanaitis
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