@fabulous71 you are theoretically correct about california registration. But show and display is not an option if the car is not currently on the list. I attempted to petition for the addition of a car earlier this year, and there is no one to petition to anymore with gov't cost cutting. There is no one in the role, and so there are no additions being made. If someone finds this to be incorrect, I'd appreciate information on how people navigated the process.
