David,

The only reason I can think of to run a "can" type muffler/pipe is for noise a 4-stroke. I have never been a huge fan of the flexible ones as they will break over time. I also know that they will last longer if the motor isn't soft mounted. One issue we ran into with the larger 4-strokes was that as we went to softer and softer mounts to compensate for the vibration that we broke more headers. This is when we started to see the more rigid headers and the pipe immediately behind the motor. This arrangement worked great and was basically bulletproof.

Most of the purpose built mufflers are very light, so I don't think you'd have an issue running either.

Arch