I just bought a 2006 A4 and want to know if I can still add NAV at a reasonable price. The dealer told me unless it was factory installed before I bought it, it would not be available to add after. They said that the fiber optic cables are not installed in all the cars. In order to add NAv to my car, he said it would cost $5000-$8000 US. Does anybody have info on this? Thank you.