This still leaves you with ONE key that will start the vehicle. As mentioned earlier…you can initialize the GM to operate the central locking system with your old key…but it will no longer start the car.
And you won’t be able to keep your old key charged since it no longer fits the ignition.
God help the next owner if you ever sell…because if they need a 2nd key (remote or non remote) they’ll never be able to order one from BMW because they use the vehicle’s VIN to retrieve the encryption for the EWS transponder in the key, the DME, and the EWS control module…and now, your VIN info (which BMW has stored in the database to replace keys, ignition, & door lock cylinders) no longer is a match.
Doing this will basically create a Franken(stein)-Key. It may be alive…but it’s terrorizing the villagers!