Custom Car Alarms have installed the alarms and stereos on all the vehicles I've had over the past 12 years. My Honda CRV was broken into and vandalized (should have hidden my portable GPS unit) recently. I woke up when I heard the alarm and the thieves departed with only the GPS and an old iPod (glovebox.) My stereo, while vandalized still worked. It wasn't stolen due to the excellent installation that was done by Custom Car Alarms.
Pros: Easy to find, large workshop, fast friendly service