The SEC-150R is the sought after one because it has built in motion detection / radar sensor. So it sets a perimeter inside the car and outside. Is someone gets to close it will chirp at them and if they don't move, the alarm goes off. You could leave your windows or sunroof open, and if someone sticks their arm into the car when armed it can sense it and set the alarm off.
The Alpine Alarm SEC-150R (only one with radar in its last gen) comes with all GENUINE ALPINE COMPONENTS. Original box for siren and for entire unit.
I can't find the owners manual but can send a PDF LINK to download it.