Trouble with comparing the performance of Iridium plugs with standard ones is that invariably the plug being replaced is old and worn out. The difference felt could well be just the fact it's a "new" plug, rather than the fact it's iridium? It's quite possible that a new standard plug could well have had the same positive benefits?

TBH, I've tried NGK iridium and standard plugs in the Ten and noticed no difference. As I tend to swap plugs annually anyway, I've come to the conclusion I'm probably better off sticking to normal ones.

The main reason iridium plugs exist, with their hard coated centre electrode, is to extend life and enable cars to have the impossibly long service intervals that they now have. They were never created as a "performance" plug as such, although they are invariably marketed as such.

However, each to their own, and if you feel it makes a difference, then use one. After all they are only �4-5 more, less than the cost of a gallon of fuel...

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