This can be integrated with your stock alarm on a mk4 golf, r32, and bora.

Basically its a motion sensor, any heat movment coming to close to your car it will beep once for warning, beep twice (your alarm that is) and then go off.
Fully adjustable, probably one of the better ones on the market out there - also imported from the US. I have one in my car myself and have installed about 7 of these so far with no issues.
Full instructions online for mk4's to install however can be connecting to any aftermarket alarm as well. FOr stock alarms the first/second beep will only be alarm straight off so needs to be adjusted accordingly (so say only if they are looking inside windows etc). Yes that sensitive
I would highly recommend this!
$55 and its yours

Basically its a motion sensor, any heat movment coming to close to your car it will beep once for warning, beep twice (your alarm that is) and then go off.
Fully adjustable, probably one of the better ones on the market out there - also imported from the US. I have one in my car myself and have installed about 7 of these so far with no issues.
Full instructions online for mk4's to install however can be connecting to any aftermarket alarm as well. FOr stock alarms the first/second beep will only be alarm straight off so needs to be adjusted accordingly (so say only if they are looking inside windows etc). Yes that sensitive
I would highly recommend this!
$55 and its yours