There is lots of ways for alarms, My favrote is mongoose, but you could always get a gsm immobliser and or finger print id immoblsier, no reason why you can't use these systems together.
with the Gsm immobliser you can stop the car via sending an sms to the car. The finger print can store up to 30 prints and maybe abit $$ at the moment around the $440 mark of the top of my head.
But it can still be towed away, in the case of organised crime not joy riders.........so the best way I belive is
A: Mongoose M80 (3point) or M60 (2point) and Insurance