You will need to do some wiring harness work as you will now have 5 glow plugs instead of just 4.
There will be other little nits that will pop up, I just can't think of them at this second. (from my 240D into 300D project that I abandoned)

**I think I would still bide your time and wait for a 240D engine**

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John