I have them installed. Prior; I inspected old plugs, (autolite platumum) that had about 3000 miles on them that were ok, but did show some uneven buring. I then inspected the piston tops & cyilnder walls via a borescope. The walls were fine, but piston tops showed a little more carbon/improper fuel burn build up that I would have liked. So I gave them a try & then removed/inspected them after about 500 miles. The plugs showed very clean & even burn. All plugs looked exactly the same. The piston tops looked a lot better also. A more even & complete fire pattern. It looked like the piston tops had become cleaner. I did notice more power, but I also changed plug wires & a slightly hotter coil. I plan to keep them, I like'm. No gaping; just install & go
