Question there's a port under driver side dash next to the tire reset button that says maps?!! What is it for?? I called the dealer for a navi update they said I need to purchase a one time use flash drive and pay for the labor and its around 300-350 to do this??

 

Depending on your year GS, the maps are updated via USB. If I remember correctly, they have to hook it up to the Techstream machine and open up the port to download the map to the internal HDD.