I have an '02 with a Mach system but it doesn't say 460 on it so I am not sure if this will apply to you or not but when I tried putting in a Ford MP3 player it would not work with the factory amps and I had NO BASS at all! There was a port to plug the cable for the amps into but all it did was hold the cable, there were no pins in the port to go into the connector plug on the cable.
I got my MP3 player off of eBay and resold it there after I came to the conclusion that I could not easly get it to work properly. Luckly, I made $70 in the resale and the guy who bought e-mailed me afterwards saying it worked perfectly in his Explorder.