歐洲車極速的疑問

It is an agreement between the four biggest car manufacturer in Germany. They are Mercedes-Benz, BMW, Volkswagon and Audi. I think Opel is not one of them. Most of their cars are automatically locked at 250km/h as their max speed. So that, the other manufacturer like Lambo, Alfa,....can go exceed 250km/h, due to they didnt join the agreement.
Hope i can help!