I’m toward the end of process of registering mine now. You’ll need to have a VIN verification done which can be done by the DMV or CHP or private companies that do it. I went with the latter for speed. You’ll also need a smog check as mentioned and pay any additional sales tax if the rate where you bought is less than your home rate. Last year I did the same process with a new GT350 I trailered back to CA from AZ and it went smoothly even with less than 100mi on the car. Not so for the Cadillac. It failed the smog test with 600mi (I drove it back from AZ) on the car due to O2 monitors not ready. There’s a TSB about this problem I posted in one of the threads several weeks ago. You can try to do the readiness procedure drive cycle in the TSB which I attempted with no luck. You can also talk to the CA smog referee (also mentioned in the TSB) and they may be able to waive the car and issue a smog certificate. If the car has more than 1000 miles on it, the waiver can’t be done and it becomes “a warranty issue” and you’ll have to work with dealer to drive it in a way to activate the monitors. In my case, I stopped driving the car at 630 mi when I scheduled the referee appointments( there’s a phone call appointment after which they will schedule a visit to the nearest available referee location). Monday 11/29 is my in person appointment to have them issue the smog certificate

and then complete the nearly 2 month journey. Then I can finally refinance my loan as they require the car to be registered in my home state. Luckily rates have been stable during the delay.