I know someone who brought his 92-ish year model Canadian spec Japanese car to California when he moved here. It wasn't a big deal except that his car didn't have motorized seat belts that US spec versions did. They didn't make him change the seat belts, but they did require a statement from the manufacturer that that's how the car was originally delivered. No problem with Canadian spec emissions equipment. It did have to pass a smog check check.
As a California resident, the strictest requirement is that it have more than 7500miles. You can't bring in a new car that isn't identified as a California spec car.
says to contact a DMV office regarding importing a car from another country. That should be fun.