I dont think you can physically steal the IS x50 (unless someone tows it) ... if someone breaks into the IS, the engine immobilzer activates, meaning your car engine shuts down ... hence rendering it useless. Am I correct in my understanding?
Any car can be stolen if an experienced theif wants it.
I had the early warning lo jack installed only $650, now if the car moves more than 10 yards, they call me,send emails, call the house phone, next of kin gets notified. I took it for warranty work and forgot to leave the lo jack receiver(a small device that I have attached to the key ring) I got notified almost the second I left the dealer ship. So If it gets towed I will get notified immediately.. An extremely great investment that was very affordable.