Most alarms don't come with a tilt sensor, but you can add one. My DEI works fine. And lol at it going off when a car drives by. A car would have to drive by FAST within a few feet of yours to actually tilt it, and then not enough to set off any alarm I have ever known of. That's one of the funniest things I have read here.
Chances are that 90% of thieves aren't going to jack up all 4 corners of your ride at the same time unless they really want your stuff and know you have a tilt sensor.
Lojack is okay, but a real GPS tracking device is much better. I forget the name of the one I see at the local shop I go to. It's not cheap, but it's SWEET.
Oh, and make sure you have a 2-way alarm, so that if the tilt sensor does get triggered and the alarm goes off, you will know.