If CA won't register it directly, make sure you do the dirt legal registration with a Montana LLC. Costs more, and has an annual cost, but makes it so there's no legal 30 day residency requirement register in state since it's registered to an out of state LLC. You can then register anything you own to that LLC as long as there isn't a leinholder. It could work out with the sales and excise tax savings depending on your state. I'm lucky, got mine registered in MA, apparently they don't care if the certificate of origin says off road only.
