The RFID key security system is one of the best in the market and i'd say much more reliable than a tracker. The reason, as far as i understand, is that you must have the key or the car in your possession in order to get the car started i.e. the thief (perpetrator) must steal ur keys or ur car (by pushing it) in order to start it.
This system + steering lock (comes with all cars) is probably one of the best defenses.