A couple of points...
You only need to undo the manifold/cat joints... A six sided 16mm is essential for this. Get the exhaust hot as well.
Whether you need to remove the exhaust or not is a moot point. It frees up alot more space for access to box/engine bolts, and for manipulation of the box... Why crush your hand against summat that could have been removed
Again, access to the selector mechanism is sook much easier sans exhaust.
Equally you don't need to remove the prop shaft, but if it slips out of the centre bearing, it's really easy to force it back in without realising that the splines aren't correctly aligned. This will cause no end of grief later.
Have done two Omega clutches on the drive, there's the easy way and the hard way. Clear as much space as possible and get the car at least 18" off the ground or you'll never get the box out from under it. And ideally take someone with you, because now is not the time to squish yourself