Should I go to traffic court or just get my car registered in California and pay the corrective fee?

Depending on the courthouse, some bench officers offer a reduced fine if you plead "guilty" or "no contest" at your initial traffic trial appearance (arraignment). You should run the costs and see what makes sense for you. In California, after 30 days, you are supposed to get a California's Driver's License and register your vehicle in the state, although many people do neither.

This is courthouse dependent on what will happen. Get your license and registration and hopefully you will only have to pay correction fee.

If you are living in CA as a permanent resident you need to register your car in CA. If you are purposely registering the car in WA to save on registration fees then that is also wrong. I would say go into court and tell the judge you registered the car in WA but I'm guessing you primarily live in CA so that will also involve you admitting you are trying to get away with not paying the CA price. Not a good idea. So unless you truly are a WA resident only temporarily in CA either 1) Pay the CA registration and get a dismissal for $25 2) Pay the fine of a few hundred bucks and be done with it 3) Hire an attorney to resolve it for you which may end up being cheaper than the fine as some attorneys who regularly go to the courts will handle fixit tickets for as little as $100 because they involve so little work. Good luck.