Yeah, you can swap mufflers, but even with the Ventilator AC it's not tuned as stage 1.

As the OP's tech stated...you can add slip ons without tuning, but he did not say it was in fact the same as a stage 1 tune.

 

The street cannons are 50 state legal so I imagine they have a cat in them. That means you're really just getting something tuned to sound a little better but still restrictive. I would think no tune necessary regardless of motor.

 

The cat is in the headers, not in the slip ons. see copy of parts book.

 

This is on the website. I wonder whats up with that? Seems like the MOCO is getting criss crossed on the literature.