I picked up a set of NGK 2647 laser platinum plugs before fully researching the issue, and wish I had the Denso laser iridium now. I’ve passed the return period, so I may to drop in the NGKs in my 2008 Prius (145,000 Could wait a week to get the Denso plugs, and sell the NGKs on eBay. Would I be sorry to go with the NGKs? We’ll hold on to this car as long as we can.