To make sure we're on the same page, when you say "perimeter" you're referring to doors, hood, and trunk, right? Some of the aftermarket alarms refer to a "perimeter" sensor as the RF sensor that could be used with open windows and soft tops, where if someone reaches in to the "perimeter" it triggers the alarm. I'm not aware of any OEM systems including this feature. I do believe that all standard SHO alarms have the door, hood, and trunk ajar perimeter sensors.
-Rod