the guy in financing at my ford dealership convinved me to get lojack as i was working out the final details of my loan stuff when i bought my x. first he asked for $700, and i said, no, but took it at $600. i know, i know, i got raped. if you go to the lojack site, their retail price is $600.
anyway, it's just a little transmitter box, probably about 3'x4" in size. you need to take it to a authorized lojack site every 4 years or so to have the system checked out and for the backup batter to be replaced. i think that procedure costs $30.