The Z2 also has the ability to integrate your iPod, Bluetooth phone, XM and/or Sirius, rear camera and much more. I also have it so that it integrates with my headrest mounted rear entertainment systems.
I'm very glad I went with the Z2 rather then the factory Nav. I was working with Webasto for a couple weeks trying to find integration kits for the features above and nothing was coming up. I even called pioneer to ask about it and they told me they didn't have anything, that I would have to go with something after market but that it still wouldn't integrate seamlessly with the factory Nav.