Have you got a set of Irwin bolt grip removal tools ?, because believe me you are going to need them as most of the bolts are going to be tight or seized, seriously, get a set and never be stumped by a rounded bolt head again.
Right, jack the car up as high as possible, support with axle stands under the rear jacking points, the four long bolts going through the sub frame are the biggest problem, with the two outer ones going through the hub, the two inner ones need to be got moving before you take out the bolts holding the frame to the body, but the frame has to come down to get them out.
I found the way to get them out was slacken the nut to the end of the thread then get the bolt moving in its bore with an irwin socket on the bolt head, lots of wd40 and even a jack under a long bar to get it turning, it will then knock out, (Dont think you can just go straight to the knock out stage).
Be a good idea to undo the bias valve before you drop the frame down as these can be tight little buggers.
Make a careful note of where the rear brake compensator pipes go before you disconnect them (if you're going to) and be ready to have the unions round off wen you do!
I tend to put the long bolts through the middle of the subframe (that hold the radius arms) in from te other side when reassembling, so they can come out without dropping the subframe or the tank. Remember where the washers go. Also, be careful the points of the bolts doing hi the tank on reassembly. If you remove the compensator valve linkage (it's easy to break the plastic link), it might need setting up again. The manual explains how, but the link needs to be slackened off and then with the car at some specified load condition, hang a weight on part of the linkage before tightening it up again.
You need the wheels off to get at the outer bolts, putting it on axle stands or blocks of wood under the rear jacking points gives you more room to work, use a small jack to support/move the hub.
If not for the bolts usually being seized it would be a straightforward job, the linkage just needs a little attention as to where the washers go, and as these can seize up clean them properly and a good coat of copper grease on the pins.
The Bias valve can be left connected and moved out the way if your lucky and careful, if you have to disconnect then as avocet says make a note on connections, and DO NOT let the brake system drain out because the ABS causes bleeding problems, lose as little fluid as you can.