dont have to drain all the brake fluid out, but whilst going about it if it hasnt been chaged for a while might be worth doing!
discs r held in with 2 hex screws, calipers are bolted on with 2 bolts, but make sure you get the bolts with the 16v brakes as they are a diff length to ur rt ones so need them. can just clamp the brake lines so fluid doesnt piss out, then once attached bleed the brakes, obviously topping up with brake fluid as will need to fill the calipers.
pads just slot in as on rt brakes, infact as far as i know the pads are the same for the rt and 16v! well there was only one code when buying mine in the local car spares shop!
hope it helps, not a hard job at all.
pete