I love how you bother to get that link when it would have been quicker to type an actual response. I also love how you assume cause I ask such question, that I haven't researched or done my own reading but I have, and I'm still left asking the same question. Taken from the first hit in Google: "Copper spark plugs are generally considered to have the best performance of any spark plug type. This is potentially different from what advertising companies suggest, but the other metals are, unfortunately, not as conductive in general as copper is. Platinum and iridium plugs are more likely to overheat, which causes damage to the plug components and can compromise the delivery of the spark to the engine block." ^This suggests that copper plugs are the way to go.. But then, taken from NGK: "The motive behind tipping spark plug electrodes with precious metals was purely performance driven. The smaller the centre electrode, the better the spark plug performs. Reducing the centre electrode diameter of a standard nickel alloy spark plug, although easily done, would result in a very poor and unacceptable service life. Using precious metals, NGK were able to decrease the electrode size whilst actually increasing service life. In doing so the spark plug was able to achieve performance benefits previously not possible." So believe it or not, even after you posting your very helpful link, I am still left asking the same question.