I've had my empeg installed for nearly a year now and have recently been the victim of an attempted theft. I never normally use the passenger door (hey, I am driver after all!) but recently when I came to open the door to put some stuff in I noticed that someone had tried to punch the lock in but had failed.
I have to say it must really take a sad individual to break in a car on the off-chance there may be a stereo hidden under the seat. Given that most pull out stereos will be ancient by now and not even worth enough to pay their drug dealer. That is assuming they weren't trying to steal the car. In which case, good luck, it's got no real clutch left to speak of and very worn out diff bearings. So the concept of Joy Riding will be totally lost on them!