I have a '00 mustang, incorporating the stock amps, I used the metra wiring harness and I wired the front speakers together to a 3.5mm stereo jack, likewise with the rears. Im using a Auzentech Prelude X-FI 7.1 sound card. The audio sounds wonderful through the front speakers; however, with the fronts plugged in to the "front" input on the SC, the rears do not output sound with them plugged into "rear". I tested them both individually, front speakers plugged into front input works, rears speakers plugged into front input works, front speakers plugged into rear input works, rear speakers plugged into rear input works. They will not both work at the same time, though. Also, using the supplied program with the SC, in 4.1 mode, and both front and rear speakers plugged into their designated input, I tested them and the results were, one front speakers plays and one rear speaker plays. I know I can wire them all together and use the line-in for stereo sound, but I want to use the sound card to it's fullest capabilities. Any thoughts?