The incentives and rebates for hybrids apply only when buying a new car in California. There's no incentive or rebate for buying a used hybrid. If you have a hybrid you can drive solo in the carpool lane but you have to put those ugly decals on your car. They're really ugly and you need 4 of the same decal. There's no incentive for personal purchases of Diesels or alternative fuel vehicles. Maybe for fleets.

Diesels and anything approved to not run on gasoline aren't subject to biennial(sp?) smog checks. Hybrids are. I don't know how they dyno test hybrids. Maybe hybrids have a smog test mode.

It's really easy to register an out-of-state car in California as long as the car was originally sold in the US. No hassles for Diesel models not originally offered in California. It doesn't cost more to register an out-of-state car you bring when you move to California. If you buy an out-of-state car as a California resident you will owe state sales tax or at least the difference between California sales tax and whatever you paid to another state. There's a cusory inspection of the VIN and DOT labels and of course a smog check if the car runs on gasoline. They won't ding you for California only emissions equipment not being in the car if not originally equiped. There's no other routine inspection of cars in California. Brakes, lights, horn, body perforations... none of that unless you resurrect a salvage title car.

About the only thing I wouldn't do is bring in a gray market car unless I owned it before moving to California.

Sixto