...in-dash units? Is Pioneer AVIC-N3 IN DASH GPS navigation compatable with Pioneer car dvd in-dash units, i.e. Pioneer AVH-P7800DVD? If so, what would I have to get, i.e. DVD/CD navigation receiver, etc? I would just get the Pioneer AVIC-N3 unit but it's screen size is 6'5" and the Pioneer AVH-P7800DVD screen size is 7" which is personally better for me.