Pin Head said:No performance gain. The basic reason is that a higher voltage spark doesn't produce any more power than a lower intensity spark because all the net energy released is in the air/fuel charge and all you need to do is initiate combustion to release all of it. Even if you have a "high energy" system doesn't mean that the running spark voltage will be any higher. The spark gap, compression and the air/fuel charge determine the spark voltage.
The way it works is that if you have a high compression, super/turbo charged engine, then you will need an ignition that is capable of producing a higher voltage in order to ignite the fuel. Most stock engines don't need a high voltage ignition.