do i simply unplug the battery and remove the old and plug in the new. then switch on the engine and leave it for a moment.

 

Suggest you speak to Someone in 'Technical' @ Subaru UK on 0121 522 2000 or call your local dealership or try mine (Westaway) on 01604 847245.

Good Luck

 

Why are you fitting a new ecu.If it is a possom then it needs programing to your car. Speak to Bob Rawle He seems to be the best.
(BR developments).If it is just the same as the one already fitted then just plug it in without the keys in. Then start it up.