Couple questions about BT GPS for Mogul and Google Maps

[machtenx]

1. What are the best GPS units to use with Google Maps as navigation for in the car?

2. If I buy only the GPS hardware and not the software will it be automatically recognized and usable by Google Maps?

3. How well does GPS work with Google Maps directions? If you get directions do you still have to click forward to the next turn by turn direction or is it done automatically based on where you are?

Thanks for the help!
Matt