[Noah930]

As others have said, smogging the car is your biggest hurdle. California doesn't care about things like working lights, doors, tread on tires, etc. There is no safety inspection, like most other states require.

That being said, when you register the car, you have to take it the DMV. They want their money, but they also check for various stickers and the VIN, to make sure the car is federalized and isn't stolen. I haven't brought in a car from Canada so maybe there's even more to it, but when I've purchased vehicles from out of state, the DMV just wanted all the correct stickers in the right places.

Because I was missing one stupid sticker (on a motorcycle, no less--it doesn't even get smogged!), I had to make an appointment with the Highway Patrol. Pretty much to again make sure the vehicle hasn't been stolen, but the officer has wide berth to inspect anything and everything else on the vehicle if his mood is so inclined. That's where you might get into trouble.

Once you pass the DMV hurdle, you then have to smog the car. All vehicles up until '75 have to be smogged. And then every two years thereafter, as well. There is a visual inspection (the tech checks to make sure everything looks stock--so that part is up to the acuity of the particular tech). Smog shops are all independently run; they are not state-run, as in some states. And then there is the typical sniffer test. Technically, your car only has to be as clean as mandated the year it was manufactured. If you have an engine swap, it has to have all the emissions equipment from that more recent model year intact, and has to pass the sniffer standards for that newer model year.

There's a historic plate option, but I think you still have to get the car to pass smog once (when you apply for the plate) before you're exempt from the bienniel checks from then on.