There's a harness that goes from the head unit to the amp; there's a black and a grey plug and you can remove the head unit. From the amp, there are 2 more plugs that connect the amp to the factory harness that you can remove. Outside of that, I don't think removal is very easy as it's all integrated into the body harness.
Side note: Anyone looking to run an aftermarket head unit, you MUST remove the factory amp and plug the head unit into the plugs mounted up in the dash. Took a while to figure that one out...