So, if there are no gains in power from spark plugs or anything of that nature, then what is the difference in all the diff. spark plugs, why buy one brand over another except for how long they last?? I'm nowhere near an engine guru nor do I claim to be, but I know that I had the stock plugs that Honda uses and then I switched to the bosch +4 and then back to the stock honda ones and back to the bosch's and there is a difference.