My '03 still has the OEM plugs at 42,000 miles. Bike still cranks and runs well and still gets the same gas mileage. When I get around to replacing the plugs I'll go back with NGK. :wink:Toyo said:Funny you should ask. I just pulled out one of my Iridium plugs yesterday to look at how it is burning. They have a little over 40k miles on them. They were still in perfect shape and still in the same gap setting. If I would have put in regular plugs I would be replacing them every 15k miles. For me thats 4 sets almost. So they have paid for themselves already in my opinion.