avic-n2/xdv-p9 disc changer

First off let me say welcome to the forums. Hoefully you will find this place as entertaining as the rest of us. Okay, on to you topic. If I remember correctly you can basically plug and play. The XDVP9 is the older version of the XDVP90, but I think the difference is the 9 came with the IR sensor and remote where the 90 does not. I believe you will need the A/V cable that goes between the AVIC brain and the DVD changer, which you should already have. As for the XM Tuner and the P bus. All Pioneer XM Tuners have what is called a pass-thru, meaning an in and an out. So if you add any other sources, i.e. Sirius Tuner, Ipod Interface, yada yada, you will run the P bus out of the other source into the input of the Pioneer XM Tuner. Hopefully this helps more than it confuses. If you still are having troubles let me know and I will see if I can help.