Im gonna get a new gti soon and was wondering if anyone has purchased the dvd based navigation system for the extra 1,800? It seems really cool but i havent seen one in person since my dealer only special orders them. Are they worth it? whats the size of the screen and does it only play dvds when the car is stopped? How good is the navigation system and does it cost anything monthly? These may seem stupid but im curious. The dealer doesnt seem to know crap about em.