Guys, it's sad when I see stuff like this. I see it a LOT in the years of installs. Even from shops saying they will take good care of it. Make sure you are not getting screwed.
I recommended that northstyle buy a reverse harness from metra and wire that into the stock wiring. this will give him the factory plug once again. Sad to see this being done.
Metra Nissan Car Stereo Harness - 71-7552 - Rakuten.com
Send me some photos of the stock wires and I should be able to tell you some of them. There are sadly a few wires that are the same color so be careful. and don't let the wires touch as 2 are going to your can bus system, tapping them to the constant 12 volt can fry the computer.