Cold air intakes can make batteries harder to replace K&N air filters are good about tweaking Air Flow Sensors, making them do weird
stuff Aftermarket stereos give another element to disconnecting batteries and dealing with wiring.
Aftermarket stuff:
stereo deck + amp + speakers, backup sensors, second dry cell battery in the trunk, and one of those $ 70 devices that is suppose to keep your primary batter from dying because you left your
stereo on too long - do nt remember what its called.