The back of the factory radio has three spots for plugs, but in the dash where the radio goes...well there is only two wiring harnesses, one of which still has the plug and the other is missing the plug and all wrapped up in electrical tape.
There was an aftermarket radio already installed, the power/ground/memory/speaker wires were all hooked up to the one harness and look to be correct according to a wiring diagram I found, but I don't think it is correct since the volume is very quiet when the aftermarket radio is turned up half way. It should be much louder than it is....and if you try to turn it up any more the speakers start to crackle/pop. Oh and they have no bass at all either.
Well here is a pic of the wiring you asked for. I also took a pic of the speaker/tweeter on the drives side door near the mirror. It says Mach Audio System, but I'm still not sure if its the 460 or the 1000?