ECU-Auto box on 92 520 M50

[scoop2004]

My fecked 2.0 M50 is gonna be a pain to fix,replacement head needed and TBH i think i'd be better off just changing the whole engine,thing is,if i was to do this i'd change to 2.5L, for 2 reasons

1.the only E34 in my areain the breakers yard is a 525
2.if im gonna spend 2 days solid working on the car i may aswell gain something from it

problem is i know nothing of BMW ECUs. 3 questions

1.Does the engine ECU control the gearshift points on the auto?
2.Are ECUs driect swap from 2.0 automatic gearbox ECU to 2.5 manual gearbox ECU (both 1992 cars)
3.Do i need to change any other parts when changing engine (IE,on mid nineties UK fords the ECU is matched to the cars key so u cant start the car if u use an ECU from another car without the keychip)

[scoop2004]

Nobody know??