Modifying a spark plug - GIF

[nova_robotics]

I've never had success with different spark plug designs. Things that my intuition would say would be better have usually made my cars run like crap. I've seen lots of claims about improved power from weirdo plug designs, but the real world dyno tests never seem to make any difference, or cause misfires. It's like gapping a plug. Intuition would say biggest gap to ignite the most gasoline at once is best, but that's not the case.

I want that spark plug tester though.

Edit: Okay those plug testers are on Amazon for like $38 Canadian, probably a lot less if your country uses real money. I just bought one.