hey there, well ive gone to a million places and they all tell me the same thing, i want my bose unit out and i want a dvd/mp3 system in it, but they tell me that if i remove my bose my navigation wont work? could someone please educate me on this? thanks

 

The navigation will work fine.
The voice from the navigation - not so much.
You can hook up a small amp and speaker to the mono output from the navigation system and keep the voice.

Since most good DDs have nav anyway, consider it a win-win situation with a modern nav system and usually, more frequent updates.

You do lose out of the optimally-placed factory system though.