it was professionaly installed. its pretty hard to get to and the wires are tight. i dont know what i would have to do with all of the existing wires. also, i dont know where the current sensors are and if i would have to remove them or not. i dont want to take it to a shop because they would charge me a lot since i would buy the alarm off of ebay. the place i got it from moved to a different location 30mins away but they install it for free. how much do clifford g4 avant guard alarms go for? ive seen going for $200-250.