just general not R30 specific
tailshaft is easy, 4 bolts on the diff, use 2 spanners. if its got a centre bearing unbolt that and slide it out of theback of the gearbox
drain the clutch lines via the bleed valve (or unbolt the line) on the clutch slave, unbolt it from the bellhousing
undo any earth wires, reverse swicth wires, ect going into the box. make sure you get all of them
unbolt the shifter linkage, youll probably have to take out the centre concole and the shifter boot. might also get away with not having to unbolt it.
start undoing the bellhousing bolts, using lots of extentions.
undo the gearbox Xmember bolts. this is where it gets dangerous as the box is only supported by the input shaft
everything unbolted and out of the way, slide the box back and once the shaft is free, drop it out. if its a smaller box you should be able to lift it yourself, but it sucks doing it on the ground!
umm clutch stuff unbolt the master from the firewall (careful of spilling fluid) and unbolt the linkage. then shove yourself doen under the dash and get the pedal out and stuff out