I had the ‘middle’ tracker on the M (only because it was on there when I got the car and the insurance company required it).

Did it work ? don’t know and don’t care, I had done my bit by paying the subscription and having the certificate – If some scrotes going take an original unmarked car and do whatever cosmetic / structural / mechanical damage would you really want a insurance company ‘fix it’ job back or a heap of cash / replacement car ?

Admittedly a different situation than on a classic / cherished car though

Think about what you would want before you hand over any hard earned

PS : They were happy to take my money but they didnt ring me when the tow truck took it away with a blown engine