So I've been reading over the last couple of years about the iridium plugs. Both my Gen 1 and X2 ran fine using the OEM copper plugs, so I was thinking that as easy as an upgrade that would be, not worth the hassle. Well, you guys were right. I just installed the NGK iridium plugs in my X2 and it's running smoother, starts right up, and more responsive on the throttle. It's been sitting for about 6 months and running a bit rough with the factory plugs, not holding idle. But hunting season is coming, and now she's running oh so sweet. I should have known better than to doubt the wisdom around here.