It seems like remote start and vehicle security system are 2 different 'add-ons' on the Ford Accessories Brochure.

If the price is right, remote start seems really interesting not for its remote start function, but for the "progressive car find" and "real panic sound alarm".

But I am a bit confused by the "vehicle security system" what does it add to the existing PATS? It seems like the VSS adds the "2-step perimeter alarm" and "interior IR theft sensor."

I wonder how the 2-step perimeter alarm actually works and whether the interior IR sensor is useful at all.