Its not a hard swap, probably a day if you have all the bits to hand.
Front end off (13mm 1/4" socket on a long extension for wings)
Slam panel is 13mm socket and spanner
Unplug loom from lights and earth and whip it all off
Bonnet unhinges
Engine/box mounts 17mm (I think)
Remove tunnel, sticks and seat box
Drain engine via plug in rear and drop oils
Remove rad/cooler setup
Unhook fuel lines
Unhook alternator, starter wiring etc
Remove engine
Fit new box first, transfer box is the same and tighten nuts halfway
Mounts may need adjusting if you want to use R380 in which case I do have a gearbox crossmember here for that just redrill a couple of holes I think
Line clutch up on engine
Fit fork to the box and swap slaves
Cut off old engine mounts
Bolt new mounts to engine
Drop into place and mate to box
Weld mounts to chassis in situ so its all lined up on the box
Hook up wiring if EFI its about 5 wires more for the ECU and MAF
Hook up rad (you'll want SD1 or RRC)
Hook up fuel lines
Bolt on the front end
Thats more or less it