Hi Theren & thanx for the reply. I have to be honest with you as I have only just got the Beemer I am not sure of who fits what and where on them. ( to many years as a Vauxhall Tech I guess), I did take a picture of the Alarm, but I cant seem to download it to here, so I will describe the Power sounder as best a sPossible.
It is a box shaped sounder with a key slot to turn on/off, located on the top left side (as you look at front) It is a genuine BMW Alarm system with total closure and sensors inside for movement.
I hope this helps. I also locked the car with the key in the door last night after turning off the power sounder, this seemed to shut it up so we al go a peaceful night and My neighbours still love me....FOR NOW!!!!!!!! LOL