I'd actually considered buy an OEM TV module--but a used one costs more than the Nav-TV module, and the TV tuner doesn't work in the US with our new digital signal, so it didn't make a lot of sense since I'm not interested in watching video on the Nav screen...

A new Nav-TV module, with warranty is about $250 USD, and works flawlessly for this, so I figured why not... You can actually buy an interface for another $100 from Nav-TV that would allow video over the Nav screen if you really wanted it...