Actually HKS asked Denso to do it for them (iridium) both great! (manufacturing supplier thing....)
i used both of them b4... but since i heard Bosch Fusion! mouth watering lah....
http://www.boschautoparts.com/Products/SparkPlugs/IrFusion
anyone used this B4? i heard on papers about the same value as Denso's Iridium....
Correct me if i'm wrong.