The Nav 5 will fit on the 660 cradle and get power from the bike
But electronically the Nav 5 has no audio out feature. None of the pins on the 660 cradle will give you that. The Nav 5 just isnt wired up to do that
Its designed to work with the bike and Bluetooth and that's your lot
Other that using the thumb controller (which is pretty cool i think) the 660 is a lot better spec'd device than the Nav-5 for less money.
If only the 660/665 could work with the thumb controller, maybe a software update, I'd ditch the Nav-5 in a heartbeat
Sadly Garmin have no plans in that regard
