[nialusa]

Fitting a new stereo yourself is easy, as it sounds like nothing is working from your current system, its probably better for you to blank off all of the wires used by your radio and forget about them buy an install kit which will supply you with power wires a couple of speaker wires, an earth wire and a signal wire (for electric ariels), the only wire you might wanna keep hold of is you ignition controled wire, that only becomes live when your ignition switch is on. (this is only needed if you want your radio to turn off when you turn your ignition off, if you want your radio to stay on all the time then forget this too, just blank it off).

You will need another install kit to run your amp, needed to power the sub. My only advice is be patient, make a good job of it, and dont run power wires near speaker wires (interferance)

The only problems you may come across are,
1. finding a live feed for the power wire, its best to run one direct from your battery and go through the bulkhead via the wiring loom access (you might be able to find a live feed by a unused fuse in the fuse box)
2. Getting the speaker wire through the rubber hood that goes between the door piller and the door, a right pain in the ass on my car.

Its a good weekend job.