Before DEI took over? Viper has always been made by DEI, along with Python,Sidewinder,Hornet,Wasp,Rattler,and Valet. Its not like DEI just took on Viper. As far as your continuous circuit goes. All that is is the way the starter kill relay is wired up. It is one that is a normally open relay circuit and when the key is turned on it closes the circuit via the alarm. The Viper has a normally closed circuit that when the alarm is armed it sends a ground to the relay opening the starter circuit. The "Avantguard4" that is the only alarm out there with the fuel pump starter kill is not that unique. All that is(and can be done with any alarm.even POS Bulldog Alarms) is a relay that cuts the power to the fuel pump done with a "ground when armed" output on the alarm. So there is not really any who is better or what not. They both are great alarms and both can have exact features. The Viper line is the only one with Responder Technology though. But its all in what the customer wants.