point made, but: (not to burst your bubble) I am from Miami (originally) and let me tell you that it does not matter what kind or how expensive your alarm system is down here. I have seen then break into and drive away BMWs with the siren a screeching, it means nothing nowadays, not even to cops.
The main appeal IMHO is a audible deterrent. That warns away most would-be thieves and crack-heads who are looking to raid the contents of your vehicle for quick-fix sale. If they hear an alarm, they simply won't bother. And even the cheapest alarms, if they work properly will sound off, scaring away ameatuers.
As for professionals, sorry to say, you will never be safe in a major metro city ex: Miami. If they want your car, it is thiers, no alarm, or the best alarm, it is thiers. period.
So again, IMHO, a cheap alarm that functions as it should is much better than no alarm at all. (ergo, my reasoning for the topic) Thanks marx404