Hello! I just got a 2009 GS350 and I'm trying to install my subwoofers into the car. I've done several installs in previous vehicles but have never worked with one that has a factory amp in it already. I've been searching all over to find the wiring diagram for this model but haven't had any luck. Can anyone help me out with this?

 

Trunk area below mat on pass rear is the OEM amp, but I'm not sure what the colors are for the sub. Should be a set of twisted pair wires coming off that are fairly thick ~16 gauge that feed the OEM sub. I can look up the colors for you tomorrow.