Do you think in Germany people who purchase a GTI, or any other car for that matter, keep it below 80 MPH after they purchase the car?
I seriously doubt it.
Break in has little to do with high speed and more with varying the RPM's. At 90 the car might be turning 3500 rpm which is not that high but a proper break in means varying the speed when driving on the highway to change the rpms. Proper break-in in my experience also means keeping rpm's below a certain level for a specified mileage. So in Germany that may mean not doing 180 KPH where the engine might be turning 5500 rpm or so until the car is broken in.