So what I'm trying to understand about dual-zone is whether that just pertains to multiple audio sources or whether it means that I can't send DVD video to an alternate screen and have the NAV up on the head unit at the same time. I don't care if the audio is a single source, say from the DVD, what's important is that video can play to an alternate screen while the head unit has the capability of displaying something else even if there is no audio. Like was stated before in other posts, if you have an SUV or truck and kids in the back then you would know exactly why this is important. I can't