Just got finished installing the shock sensor on my OEM Alarm
 

I just finished adding the shock sensor to my OEM alarm and i am very pleased with the results for 20$ i woul recomend everyone doing this its a very easy DIY now with a hard knock on the car (depeneding on how sensetive you set it, it can be set as sensitive as rain setting it off) but the alarm goes off. The one used was DEI 504d or 504m and you can buy it at circitu city for 19.99 or online at bimmerblvd.com if thiers enough intrest ill write a DIY for it.

Please do. I am interested. I guess I assumed there was a shock sensor in the alarm system already (I admit I never tested that!).

All The OEM alarm has is a tilt sensor and a motion sensor, this piggybacks to the motion sensor, so it can also be deactiviated when pushing the lock button two times

The only drawback I can see if that if somebody did bang the car and trigger the alarm, your tracker (if fitted) would also be triggered. Eventually if this carried on, the tracking company may get annoyed and charge you per incident.. Not sure, just a thought.

Also sometime when wagons/trucks go past slowly, they trigger shock alarms. Ive had a few cars with them on and I often just turn them off.

yea i know i sometimees see cars with them on them going off all the time, but i think i have the sensitivity turned down low enough that it wont set it off, ive tried slaming doors beside it driving my dads hummer by it (with has 4 13w7 JL Subs VERY LOUD) and that wont set it off either only a hard knock to the car so far has set it off which is what im wanting you just have to play with the sensitivity, and my car dont have any tracking system

Absolutely. Please share. Thanks.