In Ca, prolly 90% of owners have to do it every 2 years. If you live in like a rural area, prolly jus during change of ownership.
As for CAI, I live in Irvine,Ca. and everyone has turbo,intake or exhaust so Cops have nothing better to do here than hassle ppl bout it.
My friend and I installed the AEM v2 intake on his acura type S and we took it out for a spin to see how it sonded and got rolled by a cop. Nothing happened, just told my friend to pop open the hood, and he checked that it was CARB cert. and we were on our way. If cops are around, make sure to try to not run your intake in front of them. I have friends with tc's who got pulled over for other violations and got their intake checked and got a ticket for it. So yea, drive safe and slow when cops are around until a carb certi. cai is available in Cali