M50 or M50TU for my 1995 318ti??????

[individual]

Hi,
i am farely new to this so bare with me, and pla correct me if im wrong at any point.

So i have a 1995 318ti Individual with the M40 engine in which has now been garaged ready for the swap, my problem is that i am not 100% which one i should put in,
now i believe the M50B25 (the 2.5L Version of the M50) was released is 1992 with a vanos upgrade in mid 93 (M50TU) only to be replaced in 1995 by the M52 in 1995

i am pretty convinced i want the M50 for the swap because of all this obd 1 to obd 1 and EWS business, but the question is do i get one with the Vanos or not, (from which i can tell only alters mid range slightly!) and if so what extra if anything will be needed, and weather the extra hassle is worth it

and also i am about to purchase a donor car, when i have found the answer to the above and other than the engine, gearbox and wiring was wondering what else is recommended to be changed?????

thnx