Car Stereos: amp install, speaker wires, stock system

Question
I have done alot of wiring and installation, but I dont have a clue if its possible to wire an amp to an oem 08 silverado head unit. Before I go tearing into the dash I figured I would ask, I have searched for a schematic but no luck. Any answers

Answer
You can always add an amp to a stock system.  Instead of going to the stereo to pull the wires from, you need to go the speakers.  Track the speaker wires back to where they come together.  Hook your amp up right there.  You can use the switched power wire from the radio, and use the speaker wires going into the amp.  I would replace the wires from the amp to the speakers to a better and thicker grade of wire.  Ground as close as you can to the amp, and power wire fused and wired directly to the battery.  Hope this helps, Scott