to the OP....You can go anywhere and order the harness, from CC, or BB, and it should be no more then 30 bucks. It is a 17 ft harness that bypasses your stock amplifier. if you want to do the install yourself its pretty **** easy. all you do is hook up the color coded wires from the long harness with the stereo harness, then run the wires from the front radio to the rear. most lincoln's have the stock amplifier and require this harness. i ran two myself this weekend at work and its not hard to do at all.
and IMO, i would solder the wire harness's together then run it from the front to the rear, it is alot easier.