I got into a debate with a friend of mine with regards to the two major navigation map companies Tele Atlas and Garmin and whether or not they are used in proprietary factory automobile systems. From what I know, and heard, high end factory audio systems like Mark Levinson, Bose, Harman Kardon and bang olufsen which incorporate navigation into their system for cars like Mercedes, Lexus, Cadillac and Jaguar use either the Garmin or Tel Atlas software. However, my friend disagrees and says that those companies use their own proprietary software. Can anyone clear this up?