My Toyota Cressida has a sticker saying use only platinum sparks. They aren't that expensive and I've never had a problem. Changed once and it's done 280 000 kms and when I take it to Toyota they can't believe how smooth it is. Never used in patrol. I wonder??What's the thoughts on iridium / platinum plugs? Being a right PITA to change on the 'e, the 100000k life looks appealing?