98 taurus radio wiring
im trying to install an aftermarket stereo for someone but the car has the sound package in it. therefore the wiring instructions found on the12volt.com and other sites only shows the wiring without the factory sound package. the factory sound package includes an amp so the wiring from the amp to the stereo is changed making it harder to determine which wires do what. i would like to keep the sound package in the car but just replace the stereo. how do i go about doing that? i also want to refrain from buying the $70-$100 interface that you can get to make the whole thing easier but that just seems like an expensive way to go.
any color coded wiring diagrams will help