lots of good point and the only way I can see plugs doing anything is if you have a full setup. Like on my car I have screamin demon with a high output master coil and large wires as well. I can actually gap so large my pistons will slap. Also having new plugs and showing dyno gains is like saying royal purple adds horsepower. New fluid has less resistance the old so any dyno will show improvment of hp numbers if you change fluids then dyno.