Lexus Nav Update Is There A Legal Way To Update Lexus Navigation System Without Going To A Dealer?

Is there a legal way to update Lexus Navigation System without going to a dealer? - lexus nav update

I have a Lexus LS460, but I hate it wrong for a dealer costs $ 350 for improving the navigation, but only costs $ 70 and update a "off the shelf" navigation system.
Maybe someone knows the company will introduce the Lexus Nav system?