I just imported GL 450 (2007) from the USA to Dubai. As there was no navigation DVD in the system, I went today to the local dealership to get the Middle East Navigation DVD, but they told that before buying the DVD I should change "the control unit" in my car so that the navigation would work in Dubai. Is that a must? Has anyone had similar experience? Any advice? The guy told me that they would charge me from 8000$ to 10000$ to change that control unit!!! Of course, I did not agree to their service.