Exactly why we ordered our '10 GS Vert WITHOUT the navigation option. Too many $$$ and not enough good stuff. We bought a Garmin with a bigger screen and lifetime updates for less than $200.00 at Costco and a mount that attaches to the center vent/ac grill on Amazon for $20.00. We invested the difference in 93 octane gasoline!!
Side benefit, we can put the Garmin in the truck or in the '04 Z16/Z06 when necessary!!