As long as it has a security system, it doesn't matter. I don't know why they would give you the system without the remote on the key head, though. The alarm is automatically armed when you lock the doors. The motion sensors are infrared sensors that look like little microphones in the dash.
The seat sensors let it know if you are in the car too. It won't turn the motion sensors on if someone is waiting in the car and the doors are locked.
