I think some X3's did come with the alarm from the factory. Mine (2004 model) did not, and I added that feature. My X3 was pre-wired for the alarm, so I bought the kit from the BMW dealer, and it was a matter of plugging-in the components. I had to install the siren in the HVAC intake, the motion sensor in the roof, and the tow sensor under the rear floor. The dealership then had to activate the system via the computer.Alarms are not standard. If you don't hear a beep when you lock the car, you don't have one. The clown nose can be activated to blink, that way ppl would think you have one.