GreenMustangGt, I completely believe what you said .
In California, however,
even if you passed the sniffer & dyno w/ better than stock figures, you would fail the visual. The problem w/ Cali & possibly other states is that you must have a Carb-Exempt part no. for every part that is not stock for that vehicle & Yr., no matter how well it performs.
It is so stupid, cause if you car passes, you shouldn't need a visual!!! It's ridiculous. In my state you have to be rather slick about it. The smog techs generally know how a car should idle, and they pay close attention to sports cars, cause they know we're always trying to push the envelope to get MORE......
If you go in their w/ a lumpy idle, "burning Clean", they will fail you! They look for part numbers, and some parts to be factory engraved w/ the exemption numbers. I have heard that if your car makes too much horsepower, w/o the documentation of, for example, a "smog Legal
Vortech" or something and the smoggable supporting parts, they will fail you. I feel like it's a F**kin' conspiracy.
I suppose that if you can get a great tune that can alter or disguise the sound of a "big Cam", you pass the sniffer+Dyno, and the engine looks fairlly stock(to pass Visuals), plus all of the visible go fast parts, have corresponding Carb-Exmp info,
you could have a very fast, unsuspectingly fast car, that passes smog in Cali. If one couldn't hide the lopey cam, or use a cam grind that make similar hp w/ better idle, if possible.
This discussion, all of the posts has enlightened people like me, who have to navigate smog regulations in Cali. I can tell that I am among some very wise, very intelligent people here at StangNet. I have learned a lot here. Some of you guys are real innovators and have tried things that would impress the engineers at Ford
This is Research & Development at it's best, keep it rollin'