Don't know if this applies today. When I lived in SoCal in the late Seventies and Eighties, I was told Cali was the worst state to purchase a car, due to the strictest emission standards in the country. Had several friends travel to neighboring Arizona and Nevada, to buy cars.
After I bought my new '79 Ranchero from Theodore-Robins Ford in Costa Mesa, compared under the hood "plumbing" to another identical Ranchero purchased out of state. Could swear mine had additional plumbing, hoses, valves, etc. Please correct me if I'm wrong.