I replaced my original OEM Bosch plugs on my 06 R12GS last week along with a new air cleaner element. The bike has 23k miles on it (yeah, I hear the boos and hisses) -- I have two bikes that get equal time. Before doing the change, I didn't think the bike was running as good as it should -- not bad I thought, but not idling as smoothly as I remembered and maybe a bit more sluggish on acceleration. After I browsed some spark plug threads, I decided to try the NGK DCPR8EIX iridiums. Supposedly the OEM plugs are made to last a long time and supposedly 23K miles is within their lifespan. The OEM's looked pretty good coming out -- a light toasty tan color. Long story short, I'm amazed at the difference in the way the bike runs now. I honestly don't think the bike has performed as well even when it was new -- the idle is flawless and the acceleration is more brisk. Maybe new OEM plugs would have made the same difference -- who knows? What I do know is that I'll be changing plugs more often in the future. The iridiums need changing more often but it's a small price to pay for such a noticeable difference.