Happy to help!

The harness you need is: Metra 70-1786

$12.00 on Amazon.com. It lists for other cars but it will work. You do not have to split out and wire in anything at the factory amp, I did so because I wanted seperate controls for the rear speakers but straight connection will work fine and have the same controls as the factory (left and right only).

The only part that is a bit tricky is that illumination wire, read above posts in regards to that, you wont be able to use the wire in the harness but rather will need to use the 12V going to the ash tray bulb to get it to work properly, or just leave it disconnected altogether and set the unit to the brightness setting manually.