Originally Posted by 2011 Nismo#91

The best deterrent against thieves is light. Always park in a well lite area even if its further off where everyone else is parking.

Next, though expensive, get an alarm with a tilt sensor and while your at is get a shock/glass break sensor too. Alarms don't do much because of idiots who get the proximity sensor that sets off the alarm if a bird fly's by but its going to take at least 10min for who ever it is to jack up a car and remove the wheels. And having an alarm blaring is going to be a decent deterrent too.