Ya gotta do the business case and take into consideration your risk tolerance. I assume you have insurance...so a simple answer is don't worry about it cause the insurance will replace it. Then add to that the liklihood of your car being stolen (even in a higher theft rate city, it's gotta be less than 1%). Throw in the cost of a viper alarm install ($600?, I don't know...but for discussion purposes).
It's kinda the same formula people go through in California as to whether or not they want to buy earthquake insurance. There's no wrong answer...it's totally up to you. Given my risk tolerance, I wouldn't buy/install an alarm upgrade...but again, that's just me.
<span style='color:green'>1994 325i </span>- - - 75,000 mi.
No mods - - - very happy as is!
<span style='color:green'>1995 525i </span>- - - 154,000 mi.
No squeaks or rattles... unreal!