a question back at you ...
is it going in an 88" or fully grown up 109 ??
some bits i like to use ....
90na airbox with the legs cut off
TD5 intercooler
Rover 75 expansion tank
300tdi turbo to intercooler pipe and intercooler to manifold pipe plus the solid 200tdi pipe
200 radiator
4 thick washers to assist in lifting the engine slightly
a Series alternator mount and a "clocked" disgay alternator. plus 30mm spacer(s)
if using the 200 turbo it's easy to clock
if using the 300 turbo it's not so easy to clock but doable
grab assorted coolant hoses of the correct bore from your local breakers yards along with all the ford hoseclips you can rob to make up your own hoses (cut and shut)
kwikfit etc' to scrounge as much exhaust pipe as possible to cut and shut and build your own exhaust, 50-52mm bore straight through is respectably quiet when used with the turbo attached
flexible oil lines, be careful of your routing of the originals as you "could" end up with one scrubbing on the steering box drop-arm and pissing all your oil out (ask me how i found that one out)
one thing to watch for once on the road is the crank pulley hitting the front axle even with the washers lifting the engine, cast iron pulleys chip and crack, pressed steel pulleys dent/bend if struck hard, i put my cast iron pulley on the lathe and took the rear Vee completely off and 2-3mm off the front lip if i now hit the axle i think it's only with the little bit of exposed belt
if you've no idea when the timing kit was last replaced do it now or before you bolt the radiator and wings back on, buy a new crank seal to fit on the bottom gear in case that is weeping
check the spigot bush is in good condition and replace if needed
nothing else that i can think of immediately