I'm running Bosch platinum +4 plugs in mine, not because my ngk's were insufficent, but because for nitrous use, they're a colder running plug, due to the 4 electrode design, and I head that the ZEX 3 electrode plugs suck ass. But i'm definately happy w/ my bosches... never teied Densos, but i've heard that for n/a they're a good buy.