I went in with the exhaust I got done with. As mentioned I got a new tip made up thats legal. I keep both so if I go to the track I can put the cannon on. However, if a random cop pulls me over with and sends me out an EPA letter while I have the cannon on, unless he notes specifics about the exhaust, IF I turned up to the test with my primary exhaust on (the legal one), I dont know how they would tell. From what I could see, the cops simply state "youre too loud" without any kind of test, etc. Just off their judgement.
Either way keeping it legal is best. Im quite happy with the setup I have. Once I have spare cash ill invest in a larger exhaust, with less restriction that is legal.