You are going to need, Insignia or 93 - x gearbox(with transferbox) elsd (and all the gubbins with it) and the rear diff. You will also want the driveshafts and prop shafts from the car to start. How much this lot is is going to be a fair wack as they are new cars so wont be many scrappers.
Once you got the bits you will need a clutch friction plate and release bearing to mate the box up, maybe a few mods to the mounts (although they are all similar)
With the box in you will need to have custom front shafts made to mate up inner joints to old outer joints.
A mount welded into place for the centre propshaft bearing in the exhaust tunnel (preferably a nice billet assembley that bolts in)
Now the rear you are going to have run some front hubs of some description (to get a drive to them) Once thats been decided make a subframe that will mount the rear diff and mount pick up points for rear suspension (i go fabricated wishbones and top links whilst mounting the damper in the oe top hole and mount it to the wishbone on the lower moint) Make a tie bar to go in oe trackrod mount and suitably mount to chassis to enable rear toe angles to be set.
Finally mount rear diff, have shafts made as per front but for rear and have a suitable length propshaft made up. Wire the elsd to a switch inside the car to controll it.
Price f**ckin expensive, worth it? I doubt it.