Small howto for retrofitting a alarm siren.  You can use the alarm siren to enable the alarm option in the BCM. When the car is opened from the inside the alarm goes off.  And you can use ATA confirm. When opening and locking the car a beeb is sound.  This is pretty much an easy fit.  You need 2 parts. The Alarm Siren and a cable.    I ordered this alarm horn: 1K0951605C   I think every siren that looks like this one will work. Most VW Skoda and