We have the 'Tracker System' and have had for several years. This is still the only one that links in with the police's tracking system. I seem to remember that it cost about £400-£500 to have installed and then about £130 a year to keep subscribed. Rather than remove the system when you sell the van (which is a very complex process) Tracker do a deal where you can have it fitted to your new vehicle for just £99 and continue with your usual yearly subscription. We have found this gives great peace of mind and the fact that most Tracker equipped vehicles are recovered within 24 hours is very useful, particularly if your livelihood depends on your van.