Can this be done? Is it worth doing? I'm thinking it would be easy to do? I was thinking of getting an OEM Nav from salvage and replacing my head unit with it.

Has anyone done this?

very possible, also very expensive. www.x5world.com has some good pointers. do you currently have a nav? 4:3? that would make it eaisier

you'll probably need to replace the instrument cluster and retrofit the coolant level switch, and then install the new wiring harness to the trunk and install the nav computer and board monitor, make sure you purchase the one with a CD instead of the casette.