spark is spark. it all comes down to whether you're running the right heat range. like some of the others posted: they may just last longer. as far as others saying it makes a huge difference, i would love to see some data backing this up (other than the sellers). if you're igniting all the fuel in the combustion chamber with a factory plug, how is another going to make any more power? but factory plugs are @$5+ each, so what's another $8 total?