alarm help

I recently purchased a 1997 bmw 328is. It is "pre wired" for an alarm system, but it does not have one. I am looking for a reasonably cheap, but affective alarm system. If anyone has any suggestions, please send them. I found this alarm system online, http://www.savinglots.com/lotprod.asp?item=2250TLM
Does anyone know anything about this alarm system? Will it work on my bmw? How do I know if an alarm will work or not? I have found very little info about bmw alarm systems. If anyone has any info, or anything I've missed, please let me know. Thanks.

Unfortunatly cost wise a BMW alarm is the only alarm that will work on your car with the prewire. An aftermarket alarm can be installed seperately by a stereo/alarm shop.