for the first question: alarms act really wierd when they are getting insuffeciant voltage. if it has always done this, i would double check the connections to the alarm brain, and the status of the battery. if it just recently started, i woudl say the brain is going bad.

for the second question: anything by DEI will work. yes, the hornet is made by DEI, but its the lowest line. just find what suits the features you want.

on a side note: a high sensitivity is a bad thing, as you will piss off your neighbors everytime a harley/truck/aftermarket exhaust car passes by. a better idea is to locate the shock sensor to a central-most position on the car, and turn the sensativity down to a reasonable level. think about this: if soemone wanted to puncture your tires, scratch your car up, smash your windows, or whatever....and alarm isnt going to help, no matter how high the sensitivity is. the culprit will be long-gone by the time you reach the car. you only want to protect against breakings with an intent to steal the car or steal somthing inside of it. even at a low sensativity, this will cause enough movement to set the alarm off.