OK - so the installer took the easy way out and simply plugged in an adapter and called it a day. I'm wanting to cut the splices on the amp wiring and run wires from the sub output on the HU to the rear input on the amp. I've got the amp out laying upside down on the floorboard and the radio slid out of it's shell. I'm ready to make the change but am curious......

What's the easiest way to get wiring up into the radio area from the floorboard? It appears that when the wires leave the radio that they travel downward for a ways prior to exiting out the back of the console. I'm unclear as to how best to snake a new pair of wires to the radio.