As above or Laserline , never had any problems with either. Its down to how well the units installed as with any alarm.

I can only give you a price on a laserline 291 which is a cat 1 (alarm/immobiliser), £275inc VAT fitted. All doors, tailgate and bonnet protected, ultrasonics, flashing indicators, immobiliser (2 circuits) and remote central locking. Thats if your drivers door already has a central locking solenoid otherwise your looking at another £5-10 part + labour for fitting.