Uh... simply use it's real-world stats. If it's designed to stop small arms fire, Armor:2 to occupants... if more, then more.
Top speed is... well, it's top speed.
Cost is probably prohibitive, and probably should be.
Air Filtration System sounds like an aspect that can be FP'd to automatically resist most chemical/biological attacks of a non-pervasive, non-supernatural nature, and a +2 bonus vs anything particularly aggressive... and so on for anything similar.
Apply a relatively high burglary DC for breaking into or hotwiring the car, on the assumption that it's got better-than-normal locks and alarm systems... and you should be done.