FYI - On one of the major LandCruiser sites - IH8MUD, a vendor who has done dozens of the E-Rod swaps stated that CA no longer allows these swaps! I had also read, that GM stopped making the smog legal E-Rod swap kits.
Out of state registration was mentioned earlier, but that has issues also. We live in 2 states and have multiple vehicles in each state. Sometimes, we will end up with driving one of the cars registered in the other state for a few weeks or longer in the other state. Cops do notice these things, and tickets are a revenue source, so it's a joy to be asked by a cop why you have a license for one state, while driving a vehicle from another state! They can and do write fix it tickets, and make the driver show a judge why!!! This has only happened in CA so far! Remember, you can only have one drivers license too!
I also know that if the vehicle is stored/used/kept out of the state, you can keep and renew the CA registration, but not have to smog it until it returns!!! My daughter has her car out of state for school, and our motorhome is stored in Montana at my sisters house, we just registered both without smog tests. There is a section on the CADMV website that addresses this situation. Parts of Nevada and Arizona are considered too close to CA, and CA makes you return the vehicle to CA and smog the vehicle anyway, or will not renew registration. As our vehiles are well out of the range, all we had to do was file a affidavit from the DMV website, and pay regular renewal fee. You are supposed to start doing smog tests when the vehicles returns to state, but I don't see a time limit. Our RV will be out of CA for the next 3-4 years as we travel around US, and out daughters car will be out of state for 4-6 years at school.
Good luck.
PS - Faulty computers are going/have become the Achilles Heals of vehicles. MY in laws just scrapped a car for the same reason. The PCM died for the third time. None are available new, no one rebuilds them, and after the third used failed...Scraped it! Neighbor has a late ninety's Suburban with a common fault of the Check Engine light stays on due to a faulty ECM/PCM/Etc, so it wont pass smog. They are on third computer, and they all fail after a few months.
Planned obsolescence!!!