If you know someone in Washington take it there. You need an inspection from the state patrol (takes weeks for an appt). They will measure it, inspect it for numbers, and check the "stolen" database (it's instantaneous). If nothing comes up they give you an inspection slip. You take it to the DMV and they issue you plates and
registration. The only bad thing is you don't get an official title for 3 years but can still
license it, use it, or sell it. I had to do this with my 5er as a last resort. PS I had Nevada drivers
license and a Nevada address. I do own property in Washington and spend a lot of time there but no one ever questioned my residency.