It's not worth it!!! I bought an 11 Sentra special edition that came standard with the navi system, and u know what? That navi system is in my closet right now. U can go on ebay and get it for about $400. But.... IT'S NOT WORTH IT!!! It's very crappy. The radio distorts very bad, had lag to it, navi doesnt pick the best routes. But it is still a nice radio, and XM is also built into it. If you can find it in a junk yard and get all the wires and accesories for cheap, then go for it. Now as far as hooking up. The navi and XM will NOT work unless you have the antenna's plug into the back of them, and the bluetooth is a completly different plug. I have played with this thing alot. I was gonna put it into my moms 10 sentra, but the bluetooth plug is different, and u need the antenna plugs. I would not recomend it at all. If you have any questions on this please dont hesitate to contact me. I replaced mine with the Pioneer 3300BT. It has bluetooth, and I added HD and backup camera. Then u will need the steering wheel interface module, and that will let you keep the steering wheel controls, so thats about $400-500 bucks, but its a nice upgrade, and your speakers will come alive, I promise that. But I dont think you will be able to keep the factory sub, unless you go aftermarket, and wire up the speakers thru the normal output wires, and get a RCA converter and plug the sub thru that, but I dunno if that will work. Your factory sub is powered by an amp, if you didnt know.
From left to right Yellow and grey are radio antenna, blue is GPS antenna, Big grey is the Ipod/AUX plug, and there are 2 white harnesses on the right, bottom is main harness, and top is bluetooth, hope this helps.