As far as I know what is currently hooked up is stock. I've had the car since it was brand new so I know there have been no modifications to the audio system until now.
I spent over $800 for everything at this point. They said it would be another $100 or so to install. I would have been glad to pay it, but like I said, they are booked for over a week.
Waht does it plug in to though? The only wires I have left are the dimmer wire(orange/white) and navigation wires (brown, green, blue/pink, green/purple)