One word of advice before you start swapping ECUs of any description - disconnect the battery earth terminal. Then swap the ECUs, reconnect the battery and Bobs your aunties live-in lover.
Make sure the keys are out of the car before disconnecting the battery and leave them out until after it's reconnected.
That way if the central locking happens to activate and lock the car, the keys won't be locked in!
My "default safe place" is on the sunroof - has come in handy a few times over the years!
