I got a tax ID to buy my car. I was told when I bought it used that I couldn't put it in my name or get license plates without that ID. I am not a resident but am here for a long time this year. I was also told at Setar that I needed the same ID. I went to the tax office, filled out the paperwork (in Dutch of course - nice Aurbian lady helped me in line) and then waited to be called for the ID. It is really up to them if they give it to you on the spot or if you have to wait for it. I have had people here tell me they had to wait a couple of months. I was lucky that they gave me mine right away (I wonder if my Dutch surname helped
).