Cobra are the most prestige security brand in the world. With the most advanced vehicle security it is the best route to go with Cobra when choosing a car alarm. The Cobra 4138 is fully Thatcham approved and features very nice ultrasonic sensors which match the vehicles head liner perfectly unlike many other systems on the market which are normally black and out of place within the new style of vehicle interiors. The ultrasonics are also self adjusting when arming the alarm system this means within the first 40 seconds of pressing the lock button the alarm will know how sensitive it needs to make the ultrasonic sensors. This means this is the most reliable form of interior protection ever made for the car and van market.
The remote key fobs are made from a very strong ABS plastic and they are good for builders or people that are naturally heavy handed. Cobra also have many spares on the market if you ever need a replacement fob case or a new remote control if you loose any. The immobiliser unit is very strong and filled with epoxy when made so there is no bypass method for a thief to use if they wanted to steal your vehicle. The immobiliser is linked to the main Cobra ECU by a digital signal and this can't be tampered with or matched they are uniquely paired when the alarm is made in Italy. In terms of reliability these systems normally last for 10 years plus when fitted correctly.
Some helpful links when looking to buy a Cobra alarm.