Isue whit m50tub20 engine

[Silo32]

I have a e36 320i cabrio whit the m50b20 engine whit vanos and the siemens ms40.1 computer.
I have bean experiencing some isues whit the stock crank and cam sensors. The aftermarket replacement parts do not work on it and the original bmw part is like 300€ in my country(Romania). I dont want to spend that much money on a sensor just to fail aigain afte a while.
I have benn thinking about swapping the ecu for a speeduino mainly one from pazi88.
And use some cheaper aftermarket sensors.
I will have to change the engine wiering whit a m52 or a m50 or maybe make one of my own i dont reelly know.
I would like some advice from you guys, if its worth it (i reelly dont want to buy 2 crank/cam sensors and a o2 sensor for 1000€,i reely think i would be better of whit a speeduino).
I think this will future proof my car.
Sorry for the bad english:))