Aftermarket Car Alarm vs Factory Alarm: Do You Actually Need One?
Published on 19 March 2026
The honest answer from a workshop that fits both — when the factory alarm is enough, and when an aftermarket Compustar setup pays for itself.
Most modern cars ship with a factory alarm — a siren wired to the door pins and ignition. It's fine at deterring opportunistic break-ins. It does nothing against relay-attack theft, smashed-glass theft from a driveway, or any thief who knows where the siren fuse lives.
Where a factory alarm falls short
No shock sensor on most models. No tilt sensor (your car can be loaded onto a truck without a sound). No app — you find out the alarm went off when you walk outside in the morning. Siren cuts after 30 seconds and resets. No perimeter coverage on the bonnet or boot release.
What an aftermarket alarm adds
A Compustar two-way alarm adds shock, tilt and motion sensors, a much louder dual-tone siren in a hidden second location, two-way paging remotes that beep your keyring if the car is triggered up to 1.5km away, and DroneMobile smartphone control with unlimited range. You get a push notification the second something happens.
From $890 fitted for the alarm-only system, $1,290 fitted with DroneMobile. Lifetime warranty on the Compustar control module.
Our recommendation
If your car parks on a secure driveway and you live in a low-theft suburb, the factory alarm plus an IGLA immobiliser is plenty. If you park on the street, own a commonly-stolen model (Ranger Raptor, LandCruiser 300, RS3, M-series), or want phone alerts and tilt detection, add a Compustar.
