I'm running the latest disc available... I'm on my third upgraded disc thus far in my A/C.
If you have the DVD Nav, it's just a matter of holding the tilt button down long enough, and the display will motor down to reveal the navigation drive's disc slot.
As for changing the interface? Not gonna happen. The discs are nothing more than map data matched to a specific firmware/hardware combo found in our Altimas (and whatever other cars are listed as compatible for that specific disc) to prevent swapping/copying between cars, not that it really reduces piracy in this day and age anyways...
