Well its my sisters car and I just put in a HU, with a sub, sub amp, and a 2 channel amp along with some comps for the front that I am in the middle of. The amps are running off of preamp outs. I had run a couple of 14augs from the 2 channel amp to the factory harness to keep from having to fish wire through the doors but realized that it had a factory amp on it once I took the door panel off and tested it with a meter. So now as far as the comps go I am just going to go ahead and home run it like I should have to begin with. As far as the rear speakers I will probably just go ahead and leave the factory amp wired up the way it is since it has 2 sets of rear speaker (1 set highs & 1 set mid bass) with a crossover in the factory amp.