Yes the Factory alarm was disabled. The Code Alarm is the Sure Start model, probably a different model now. Is your Vette automatic trans? Autos are a lot easier to hook up; with manual you also need a position sensor for the stick. I have one like that for my Jeep, the sensor is made by a different company, from Canada (where else!). Almost all the install is inside the car under the drivers side dash. Agility helps. There are options as to whether you want the starter and/or ignition to be disabled if alarm sounds. I chose NO to that so I wouldn't be stranded if the alarm malfunctioned. We still have the pellet key to slow down hot wiring the car. Of course a professional thief will just drive up with a tow unit and drag the car away alarm blasting and all, we can just run off the idiots who don't plan ahead.