Dan- A little confsued here. The nav system plays DVD's when the car is moving? Or not? IF it does not then why don you need the $80 adapter. Oh... and why are you watching movies while driving anyway?
Normally, you cannot play DVDs or use certain navigation functions while moving. The $80 override tricks the system into thinking you are not moving so you can play DVDs and use all navigation functions while moving. The video adapter is different device that allows you to play another video source on the navigation screen.
my BASE MODEL does not play DVDs period. This is obviously something only done in the advanced model. the speedlock override allows me to play picture slide shows, dial a number, go through any/all menus, so you do not need to use voice command ONLY. Stock you will not be able to do much at all other then voice command on the fly which is very hit n miss. Dan