try
www.installdr.com
might be something there to help.
can mayb try
www.metraonline.com
might be tricky either way.
i do have a Q though....are you just needing the color for power and ground or all the speak wires too?
if you are going aftermarket systme then it would be best to just run new wires for all the speaks as the factory are kinda wimpy.
can run ground and power direct if needed.
just some thoughts.
Monty