Do you have the Mach system or not?
Essentially it entails doing the same thing. You gotta run a power wire from the battery, and then hook up a ground for the amp (use a chassis bolt in the trunk). Then hook up a remote lead for it, it doesn't need a lot of power to turn it on so you can jack it off the radio power on the RCU.
After that it's essentially finding the wires for the speakers and hooking them up to the high level inputs on the amp. If you don't have high level inputs, you are going to need to use a line-out converter. Basically it takes a pair of speaker wires and converts them into RCAs so you can run them into the low level input into the amp. Then just wire the other end of the wires that you cut into the speaker wires. It's fairly simple to install an amp because you can just kind of sit it in between the wires.
Does anyone have the identification for the different colours of wire and what speakers they correspond with? If so please post it.
That'll help a lot.
As for the speakers, that's not too difficult either. First though you will need to remove the back of the rear seat. Pull down the seats and undo the four bolts holding the back of the seat into the car. Then remove the clips around it and carefully pull out the seat. You can then pull off the carpet unit above the rear deck and get access to the speaker bolts. (Note: My 99 Sable has a grille over the speakers. If your car does too, you dont need to remove the rear deck to get at the rear speakers). Then just unplug the speaker from the small harness. You then just hook it up depending on the + and -. I would just say screw it and cut the factory harnesses off, that's what I did when I installed mine. But some argue that its easier to replace in case you want to remove your speakers and go back to stock in the future. So if you'd prefer that, go to Best Buy and get some. Plug those right into your factory harnesses and hook the wires up to the speakers.
The fronts are not too hard either. There are a few screws holding the door panel in...in my 99 it was one in the handle pocket, a couple on the side and around. Once you get all the screws out, using a screwdriver pry the panel off...it is held in by several small clips. Mine didn't come off and I didn't wanna mess with the harness for the power windows and locks so I just let the door panel hang. I had sufficient access to the front speakers that way. They have the little harnesses on them too. If you have factory installed tweeters you will see two wires going from that harness up to the door pod. Personally I would just disconnect these, because with the amp and everything you are going to get way more treble out of the front anyway. If you want to keep the high mounted tweeter sound, I'd suggest getting a new pair of tweeters because if you amplify these too much you'll probably blow them up.
but to connect them just run them in series with the speaker and make sure the amp is 2 ohm stable of course. It probably is but just in case.
What amp and speakers are you planning on using. In case you aren't familiar, the stock speakers are all 5x7/6x8"...the crazy Ford/Mazda size.
As long as you don't have the Mach there is no factory amp that needs to be bypassed so you are fine. If you do, let us know and we'll be able to steer you in the right direction.
Good luck and welcome to the TCCA!