TenaciousD, since I was replacing the entire system I couldn't use any harness. I just snipped off the proprietary connectors in the dash and snap-connected the wires to the head unit's harness. These connectors work really nicely:
http://www.radioshack.com/product.as...5Fid=64%2D3085
There is a harness that allows one to replace just the head unit and that's the Metra 70-5519. Again, that's if you're keeping the amps and speakers. Oh, and my installation was tough only because I went with a head unit that you have to custom-fit into the dash (since it was double DIN I couldn't use any of the installation kits). Taking apart a Mustang's interior is relatively easy when you compare it to other cars. Just be delicate when pulling things off and putting things back on.
ACSPONY, wiring in parallel would mean something like connecting two speakers to the same speaker output terminal at the back of your home theater amplifier. Both speakers will receive the same signal except now the amp has to work twice as hard to power them. If the amp isn't super beefy or the speakers are low impedance then the amp will overheat and shut down.
02GTKB, I hear ya on that one. Actually, one of the reasons I decided to replace the Mach system was so that I can play music loud and with little distortion over the wind noise when the vert top is down. But now that you mention the exhaust I need a sound system that can play loud enough so I can hear some tunes over my phat MAC exhaust.
