Audiovox Pursuit Alarm/Older Car

A quick question for all you seasoned installers.  When installing a car alarm in an older car ('90) that doesn't have all the newer bells and whistles like power door locks/windows/trunk/etc., is it possible to even install an alarm?  I recently had my car driver side window smashed out and I was wanting to purchase an alarm that simply has an impact/door open sensor with a flashing LED to let passer by's know that the vehicle has some kind of alarm.  I'm not overly concerned about vehicle theft (although our city is big on the rise) but more concerned about vandalism/property theft.  I was thinking of wiring a simple flashing LED circuit that would give the appearance that the car was alarmed as a possible means of deterrent but I'm still thinking an alarm is the way to go. 

So back to the original question, do I have to use all the supplied wires on the wiring harness in order for the alarm to work properly or can I simply hook up the features/functions that I wish to use?