JMO but for 'general' security that is your car doesn't really stand out for example you don't have video screens that are visible in headrests or in the center dash along with expensive rims I think a 'regular' alarm with some customized tweaks like a kill switch or extra sensors like tilt/glass breakage etc is good enough.
If your car is 'blinged out' and stands out as saying this car has lots of money put into it I think you are better off going one step above and something like a 2-way if you will be within range to know when somebody is fucking with it or even better a GPS integrated alarm that can call you cell phone when events trigger the alarm.
On a 10 year old car I think the assumption will be you haven't bothered to protect your stuff IF the car looks like money has been put into it or someone notices you parking it with the stereo thumping and speakers blaring advertising all the power the system you installed has.
I like directed/DEI/Viper, same company, but everyone has their own opinions on alarm companies for the GPS if you go that route I have seen the initial module costing around $300 or so with a monthly fee of 10-20 per month for using the GPS 'calls' or requests to alert you of an alarm triggering, check vehicle location, or if you use your phone to open your car door etc.
Directed makes 2 gps integrated alarms I think one for the viper line and one for clifford that might bring the cost down I don't know the price of that alarm with GPS combined.