I don't believe the stock muffler is strong enough to support any additional added structure. There are quite a few reports of the 35 and 55 rear exhaust mufflers self destructing as is ... especially the ones provided before they went to the plastic tube extensions. If you want a larger, quieter muffler, I would consider having a company such as Jtec custom build one for you. Or as indicated, you have the equipment so you could probably make one yourself. As a rule, any time you enlarge the muffler chamber it will be quieter.