Agree with the above. Factory immobiliser, unless specified by the first owner, it is likely not to have an alarm. When the S3 was in production, some (most?) of the insurance companies started to require active tracking (ie a live device fitted to the car, which would send an alert to a monitoring system if the vehicle moved without the other side of the unit (a tiny credit card-ish size device) present in the vehicle. As the owner carried this with them, the thought is that if it is not the owner, or someone authorised to drive the car, it will be moving without the card present.
If you had this fitted, you'd know.
A call to the factory, with the VIN, should provide you with the original spec.
