2013 Sound/speaker upgrade. head unit diagram
 

I bought a 2013 LX Sedan, and I am going to up grade the sound with Alpine SPR-60C 6.5" Component System in front doors, Alpine SPR-60, 6.5" in rear deck. Powered with Alpine MRX-F65 4-channel Car Amplifier. Also 2-- SWS-12D2 - Alpine 12" Dual 2-Ohm 500W RMS Type-S Car Subwoofer in the trunk, powered with Kenwood Kac-9105D 1800-Watt Class D Mono Amplifier, I will be tapping the speakers for signal using AudioControl - LC6i - Line Output Converter.

What I am looking for is a picture, a wiring diagram of the factory head unit.
Is there any aftermarket wiring harness out there? mainly for speakers.

Thanks