I Had tpl tracker its ok not great not good ..its like extra goodies .. by passing tracker is now a days v.easy ..
best my friend was doing.. 2 thing he also parked outside he had brand new car at that time..
he was taking off the battery at night time whenever he parked at night and taking off the main jumper from the fuse box.
its little bit hassle but its worth more then car i think..
battery and jumper are key .. then i think v.rare chance