I'm not sure about the tie down part. I know that most are trucked from Stuttgart currently as you can see the trucks on the A8 or 61. However there are still some that travel from Stuttgart via train. I'm guessing, only guessing that Euro models also have "tie downs" on their frames as well as NA models ho else would they be secured for transport via train across Europe?

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MAKDUFF3

1975 300D, Feuerrot and Parchment interior

1971 220D (RIP)