Long time since I played with one, but I had a series with a 2.5d turbo in
it once, with 7.50 tyres and rangie diffs, it flew! From what I remember the
exhaust downpipe was a modified standard part as it fouled at the
crossmember, not the bulkhead. The whole exhaust needs to be replaced with a
system of around 2" bore anyway, as the std series one cannot flow the
ammount of gas it needs to with the turbo engine.
All mounts are the same, but the sherpa version of the engine has the
injector pump sitting higher up on the block than the landrover version,
giving more clearance for the battery tray. You'll probably have to relocate
the battery (to under the passenger seat?) and remove the battery tray,
assuming its a landy version of the engine you have. All fuel lines are ok,
just a few adaptors to lengthen them to the pump.
You need to fit a switch and a relay for the high current required by the
heater plugs, and remove the oil-bath air filter! You will need to fit some
form of dry filter, possibly something like a pipercross straight to the
turbo inlet, or extended forwards into the space in fromt of the radiator??
Badger.

It can be a long job. Things I had to do when I did it six months ago

New big bore exhaust ( Steve Parker, one of his "standard" specials ),
Move the right hand chassis engine mounting point , otherwise it fouls
the injector pump,
mounting frame for the 2.5T radiator top move it further forward so the
viscous fan and radiator cowling would fit, which meant I needed the
front panel and bonnet from the donor 90,
move the battery into the box under the front passenger seat,
new brackets for the 2.5T air filter,
New mounting for the coolant header tank on inner right wing

Having said all this..

Go for it, it is well worth the work

HTH

Tim