The hardest part is actually finding the regulators and loom, once you have that its dead easy. All you need is an ignition live and earth then you're sorted!
Simply a case of unbolting old stuff and bolting in the new kit, but make sure you get the right type as there are 2 door types, the early one with the mirror half way down the door and the late type with the 1 piece glass.
3 & 5 front door regulators are the same, but the rear door regulators are different to the fronts.