Im slowly going to be putting together a system for my car, first piece is going to be the headunit., along with two 8's and an old amp I have.My question is this: I have a Mustang with the Shaker 500 sytem in it, if I buy the wiring harness adaptors for the factory speakers will they all still work? The thing I'm worried about are the two 8's in the doors being powered by those two little dinky factory amps. I just dont quite understand how the factory stuff is wired up. Thanks in advance.