Are you trying to bypass your stock amp? If not you can just use a harness from crutchfield.com or go to your local best buy or circuit city and pick one up.
you need to bypass the stock amp on a gts for the harness to work, because it fits the plug that goes into the amp, not on the plug that comes from the amp. I dont have pics but ill try to help you out. take out the glove box, ull see the amp, unplug the wires going into it, then plug ur harness into there, and ull need to run longer wires (splice) to the center console to get to ur new headunit.