replacing 350z factory nav

Ok, I have a girl that wants to completely gut her 350z stock system. It has the factory screen above the HU and the facory NAV. She doesn't like the way the buttons look that are below the screen, so she wants the panel and screen replaced with something aftermarket. I've never done a 350 before, so I'm not sure exactly what the setup is. Can the factory NAV be hooked up to the a/v input of and aftermarket unit?

Also, what should I do with the factory HU? Does anybody make a panel I can put there to cover the hole?

Thanks.

i dont beleive that the factory nav can be used with anything else, they do make a dash kit for the radio but not the nav screen if you are going to replace the stock nav screen i would probably do a new aftermarket screen in its place maybe an alpine touch screen with nav or something like that but the buttons would have to be removed ,then filled and then painted and to fit the screen in there would take som minor fabrication, also with the bose system you would have to do an intergration with the factory amp or do a complete rewire and junk the bose system as well. but definetly doable

good luck