[Pierre]

I was under the impression that the EWS from the donor car is NOT needed. The 318ti's EWS matches the key of the 318ti and what needs to be done is to program the S52 ECU to accept the signal from the car's EWS.
I have "heard" that you can also remove the chip from the donor car's key (if you have it) abd place in the 318ti's key. If you use the donor's EWS module, it will recognize the chip from the key (They match) and will send a coded signal to the ECU which will alos be recognized, and the car will start. I have not confirmed that option to be true but if it works, it saves from replacing ignition switches, door lock cylinders and the hatch lock.