Is it possible to set the Navigation to use the entire screen as opposed to sharing with other displays like audio, ac, etc. ?

Nope. I've gone they every possible option, and nothing. What I really wish was for the navigation to have birds eye view. Not used to the top up view...

time for a DDIN conversion

My salesman said he nearly lost a sale due to a customer's disappointment that the whole screen wouldn't display the nav map.

Who ever that person was is an idiot. This is STILL the biggest navigation screen in the market. Everyone is mesmerized by the size of the screen, and those who don't know the car think its a built in computer. That person who passed in the buy provably has size issues....

what made it easier for me is to turn off North direction for the map, it really bugged me how it wasnt alwaysgoing up, and with that setting it basically works the same way as 3D map so I am fine now.

take a black duct tape to cover the right part and there you get NAV on the entire screen.

What he said.

hahahah agreed. Why would somebody not by the car because of that? Its better than switching screens to see music

No kidding. The nav screen in the GS makes the nav screen in the S5 Cab I traded in look like a postage stamp.