or get one of these:
Easy Fit Car Alarm : Vehicle Security : Maplin Electronics
connect directly, but discreetly to your battery, couple of self tappers to mount the horn on the bodywork.
plus you get to "bleep" your motor from afar!
Got me one of these, holy sh1t its loud!
So easy to fit I was sure I hadn;t got it right but it really is a piece of pi55. Gonna put the isolator in the fuel pump solenoid, fit the bear trap in the drivers seat, buy a rottweiler for the boot and build a machine gun nest at the bottom of the drive. If they get away with it again they've earned it
