I've run both the Denso IT-20s and the Brisk plugs, which are in the truck now. I picked up 14 RWHP on a Mustang dyno with the Brisks and charted the pulls for Mark Silvestri at LFP. Both plugs work really well and provide excellent longevity. The biggest difference is that the iridium tipped Densos don't like nitrous, whereas the Brisk plugs handle it just fine.