That is correct, when you go to register it they will charge you sales tax. If you have a home in oregon where there is no sales tax and register it there, then there is no sales tax. Then the issue comes to insurance fraud. You have to let the insurance company know where it will be garaged. Just pay the sales tax!
The car depending on how you ordered it, shoudl be there within the 6mos mark at the latest...should only take a few months though, as long as you didn't order some strange combination.