Originally Posted by chuck65

Just think a minute. wouldn't all of the car manufactuers jump on anything including any spark plug design that would net them more HP and gas mileage over their competitors. Just another ploy to get your money. When I managed a Shell service station, we found that your best and safest option was to put in what you take out, that is, brand and heat range. I'll swear that if I were to not change the plugs at all on a customers car, 50 percent of people would swear their car's running much better. If you are racing your car you may want to run a colder heat range but other than that stick with you stock plugs and enjoy the fact that you should be able to go nearly 100,000 miles without doing a thing.

I was employed 25 years by Champion Spark Plug Company, tool & die, design, engineering department. I was on the team that developed the irridium 100,000 mile plug for Champion.