Maybe you can tell us as to why they think it isn't legal? I'm not sure why they said that. I'm sure a muffler shop should know the laws and at least tell you if it is legal or not, even if they install it for you. That being said, I don't think ANYONE on here has EVER been told that it was illegal.

Ask them why they think so.

Also, why didn't you just buy the muffler and catback at the same time? There is a catback produced by the same manufacturer as the PV. This could have saved time and money (unless you are spacing out your purchases).