mounting a versa head unit in a frontier?

I've decided I'd like to replace the stock 2008 Frontier head unit with one of these:It's an upgraded unit taken from a 2007 Versa, has 6 disc changer and MP3 jack on the face. I just don't know if it easily mounts in the same space or how to make it interface with the existing wiring. Here's the back of the stock Frontier stereo for reference:

 

Here's the back of the base Versa unit:It looks to me like the two connectors on the Frontier unit mate with the same connectors on the base Versa unit. That leaves two extra sockets on the upgraded Versa unit (the one I want to use), but I have no idea what those are for. I'm hoping they're just for steering wheel controls or something like that which would still function without needing to be hooked up at all.Anybody know if this is possible?Edit: Just read that DD units fit in the Versa without a kit. Does that mean a unit from a Versa should mount easily in a Frontier?