I purchased a car from AZ dealer. I paid them CA sales tax on the vehicle. When vehicle arrived I took to DMV where I showed purchase agreement showing that AZ dealer collected CA sales tax and then just paid vehicle registration fee. You must also get a smog done in CA for registration. Keep in mind that DMV has to do a VIN check of your vehicle as well. They can do it at their office while you wait or you can have an independent vehicle verifier do it for you. In my case I did not want to drive my vehicle to DMV (if you saw my DMV and the people and cars it attracts you would understand) so I had my BMW dealer do it for me and I just took appropriate papers with me. Keep in mind that CA law gives you so many days to register vehicle once it enters CA. Beyond a certain date they can access penalties that can in essence double or triple normal registration fees. My dealer had extreme delays in getting final papers to me so I fell into this double registration period. Keep in mind that the dates you write on the registration forms will determine the fees you pay . Most of the time these dates are hard to verify by DMV but you may be the one out of 100/1000/whatever that might get questioned. FWIW.