I'm running Denso plugs with the type-R heat range. They're ~$6/pop at AutoZone (it's listed under the general heading of VTEC, but they're actually the R plugs...heat range is 11 for the R, GS-R is 13). They seem to do OK...haven't noticed a loss in MPG, but have noticed a bit more pickup. Personally, for $6, they're awesome. NGK-R plats are SUPER hard to find under $10. I stand behind my Densos. Plust he box is cool too...can't go wrong there.