I try to optimize everything to squeeze out every last drop of energy and mileage out of the amount of fuel burned, I don't feel like I should leave free horses on the workbench when labor is free.... and I don't have that many ponies to begin with that I could just give them away \:D And simple indexing doesn't require any extra plugs, I don't get that part. Anyone used crush washers with these washer-less plugs to allow for easy indexing? I only used NGK plugs on my other engines that used a crush washer. You get some room to play with them and additional adjustability with extra solid washers.