$1,100 for the upgrade plus $400 for installation.
So, I went to ebay, and found a dealer in Dallas, Texas - Sewell Lexus - selling the 2006 DVD for $288. It arrived today, and was $296, including shipping.
Installation took less than 5 minutes:
1. run the front passenger seat all the way forward
2. turn the ignition to the on position (not running) so the navigation screen is on
3. pop the cover off the navigation system box under the passenger seat (approach it from the rear). Two tabs and the cover is off.
4. Slide the release on the upper left side of the DVD box to the right, and then push it to eject the old DVD.
5. Insert the new DVD, slide the release to close.
6. Pop the cover back on.
7. The screen will tell you to leave power to the DVD navigation system on while it updates. In about two minutes the map screen appears, and you are done.
That means my dealer is charging $4,800 per hour labor for installation!
And, making an $800 profit on the DVD!
