I have tried to research finding a place to buy the OEM NAV and haven't found anyone who sells it or who has replaced their stock HU with the OEM NAV. Supposedly its nearly impossible since there is no room behind the stock HU due to ducts for ac air flow. The OEM NAV cars actually have different ducting for air flow then the stock HU. I'm not sure how true this is just something I read in trying to research a nav solution for these cars.
If anyone finds anything out for a higher up NAV solution please post it. This is something I really want to do to my ride and the other solutions do not seem practical.