45k mile '03 F650 CS
I just recently swapped an old NGK DCPR8E (a slightly updated Nickel version of the OEM plug) for this Denso IX24 plug. Although it may sound cheesy, I can say honestly that it feels like I'm riding a different bike. Power delivery from 1.5-2.2 rpms feels slightly more responsive (although that could just be confirmation bias on my part), and the mid range - high range rpms are WAAY smoother. I no longer get that lag or hiccuping in first gear between 3.6k and 4.5k rpms. It was definitely worth the money and time.