Heres what i did, my car 94 z28, came with a factory subwoofer and amp. The wire are going through a crossover then to your speakers. I fished new wires through the rubber going into the door with a coat hanger. Otherwise you'll have to get to the crossover in the doors, and cut the wires to it, then figure out what wires you need. It's easier to fish the wires, than try to get to the crossover. Once the wires are through then you just hook them up. If you need good directions, let me know, and i'll give you specific directions on how to do it. That was the easiest thing to do, to change out the door speakers.