The RT comes with a glaring hole in the dash for a navigation unit. Ideally a BMW Navigator V or VI. These units are rebranded Garmin units, but with some extras which allow the BMW wonder wheel to control some functions. An early decision therefore, was wheter to buy a BMW unit, or a Garmin unit without the integration. The BMW units are generally 2-3 times the price of the Garmin unit, so you have to decide how much you value the integration. In the end, I decided that the integration was not worth the difference , since I would not miss what I never had. A few youtube videos did not convince me that extensive functionality was at stake. I found a new Garmin 660 online, despite its age. The money saved is going toward a seat.