you can get it done. Dude welds plugs into current stud holes, machine the front flat and the machinist drills 4 holes at 4.5" diam.
find a yr22 tarago that's wrecking and find out how much he wants for the diff. then do some simple maths. cost of hilux diff + above work vs cost of tarago diff. Unless you must have a g-series, then, you don't have a choice.