Cwise, if the G's navi screen is anything like the Acura's, then this would require the VERY HARD TO FIND RGB converter. I have one currently installed in my CL and can watch DVD's and TV as well as Navi. Basically, you have 4 signal wires going from the Navi "brain" to the screen... R, G, B and Composite. If you have an RGB converter, it will accept a video input, and output those 4 signals. All you have to do is hunt down those 4 wires and install a switch in the middle. Switch off = navi, switch on = DVD player.
That's kind of a crash course, and I hope to have some do-it-yourself instructions up soon. In anyone knows of someone that has done this on a G, let me know.
Also, Ron from StreetEffectz is very knowledgable, you can
email him for more details. He even sells complete kits with the converter, switches, wires, etc. He could probably tell you if this setup would work on the G.
2003 G35 Coupe (on order)
6-speed
Diamond Graphite / Graphite