Registration of American vehicles – small registration plate

Moin together, let’s ask a question here: I finally approved my Caddy. TÜV wanted to have 250 euros for the oldtimer report – ok, that’s already a hammer price, but accepted and checked Only the banger was on the road traffic office:153 (!!) Euro for the exemption to be allowed to screw small plates to the car. The work was 2-3 minutes, a note was printed and there was a sticker on it. That’s probably the absolute usury… Dabe i this is not a special size, but it can be used the standard registration marks for motorcycles. Have you also gathered such experiences? Greeting, Sam