It is sort of L-shaped.
On the head unit side (the angle in the 'L'), whatever fits the HU.
Right by that (about a foot at the foot of the 'L'), the connector for the vehicle harness (power, ignition, ground, antenna, etc.).
On the other end (after about 3 feet of wires at the top of the 'L'), the 8-pin connector for the door speakers.
You can tear out the old head unit, the harness that connects it to the 'premium' amp, and the premium amp and not be missing anything important. I'd recommend using them to target practice if you are out in the country. If you are in the city, it might be fun to see if you can get them to hang from a tree like an old pair of shoes (I'm not sure if the amp is heavy enough for this to work--heck, it barely weighs more than the old harness). Or, if they don't work any worse than when they were new, you could sell them on eBay.