Don't forget the other advantages of using the OEM TV tuner:

1. You can add little AV-Senders that transmit on UHF channels, eg: front door monitors, baby phones, etc.
You could fit one to say the reay of a trailer so you can see inside the trailer or behind the trailer.

2. You could add multiple video sources to your car, like play station, DVD, etc etc, all running on UHF channels, and select them on the TV.

3. The native TV tuner offers backup camera, input, AV input, and AV output (eg for rear seat monitors). Use the AV-in for an external USA-compliant digital TV tuner.

As the usability of the native TV tuners is reducing due to the analogue TV switchoff, they should theoretically reduce in price.....