I find it hard to believe a spark plug can make a noticeable differance in performance or fuel mileage. They either light the fire or they do not.
So then what you are saying is that I should never need to replace my plugs as long as they are firing. I can just regap a plug with say 80,000 miles on it and it will be as good as new.
That is not what I said, well maybe it sounded that way, but what I was trying to say is that changing from one type of plug to another won't give you a measureable change in performance. All the evidence I have seen so far is anecdotal, not measured. Again, this is my opinion, and until I see measured evidence, I will stand by it. I'm not trying to start a war here, I just don't always buy into the hype without proof.