Most of the kerfuffle about iridium plugs was/is due to the fact there are an awful lot of fake ones out there, particularly on ebay.

http://www.ngk-sparkplugs.jp/english/techinfo/fake/

A proper NGK iridium plug won't be a problem.

Having said that, I've tried iridium plugs on my Ten and they don't make a blind bit of difference as far as I can tell. Just remember that iridium plugs are often miss-marketed as a "performance" plug, but what they actually mean is that they just last longer because they have a more resilient tip so takes longer to wear away. The only reason iridium plugs exist is to prolong service intervals.

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