I just bought a DEI Hornet 554t with a 2 way pager, so if my alarm goes off, a little pager about 2in x 1in with beep like hell until I turn it off manually. Its convient, only had it installed for 2 weeks, already had my alarm going off, to where some fat ass decided to sit her ass against my car while trying to get into hers.

Also, for the best security feature I think I have is that my car use to be automatic, but converted to stick. The people that replaces it, left all the wiring for the automatic in the car, including the cluster and stuff, all hidden, and a switch is hooked up to it. If the switch is activated, the computer will think the car is automatic and will not start at all. The switch is welll hidden to, but anyways. If they want your car, an alarm isn't gonna stop them. I would also try and avoiding buying big fancy scanners and stuff to PROMOTE you have an alarm. A small LED that is visible if you walk up to the car is decent.

And I work for a retailer and I live by Alpine, except Hornet because I wanted a 2way pager.