I have not used the products from this company ,but do use something very similar from a company called Trackit247 which is pay as you go based with sim cards.and has a similar web set up
the products look very similar and the tracking and reporting is spot on.
however the unit we use from them also has an output which can be enabled via sms message which can be wired to just about anything,you want to turn on or off.
we use it with a relay to disrupt a starting circuit to prevent use of a vehicle on our rental fleet of taxi and private hire cars ,so if the rent is not paid we can just look and see where the car is,maybe we will want to recover it,or just check a drivers story about being 100 miles away and not back till tomorrow.
If outstanding payments are becoming a problem the car is remotely turned off !! and wont start
Amazing results in reducing outstanding rental payments.
we also use it to disable vehicles that are parked up and not in use for longer periods as a security measure