This weekend i will be helping a friend with an install in his challenger. The battery is in the trunk of the car which make most of the install easy. Just needed some advice about where to put the remote turn on wire. Would i be able to connect the wire to the factory head unit without being able to cut any wires by trimming the end of the wire and putting it into the harness with the current 12v source? our would i have to cut the wire and have to splice them together?