I noticed the other day that my engine idles slightly faster with the head light off so I am geussing that with the lights off the ignition system can get more power and produce a more powerful spark so I was wondering would a more powerful ignition coil increase performance and/or give me better milage at all? For example could I just switch my current coil with an ignition coil from an old vaxhaul corsa? Would there be any risk of damaging my engine at all?