I just put the GT520 in mine, and I used the diagram on
this thread for help. Getting rid of the fader switch is pretty easy- just peel back the black plastic wire sheath and follow the directions on the thread. It has a good diagram that helped me a lot. I'm not sure the colors will help you, but the wire position may. You can use a small AA battery to find which wire goes to which speaker. The speaker will crackle when it is hooked up to the small battery.
And speaking from experience, tape the antenna connection really well if you are using a cable extension (I put in the XD-100 HD tuner). It fell out when I installed the headunit and was a pain to get out. Also, don't drop one of the two radio removal keys behind the headunit when you install it. It made getting the headunit out to access the antenna cable a PITA.
edit- that is a fader switch, BTW