Iridium, Platinum and Gold Palladium fine tip plugs spark at a lower voltage so could accept higher gaps without extra loading on coil packs. Could explain these wider recommended gaps.
I could be wrong, but the plugs I took out were standard copper tipped. All my research shows the gap should be 1.30mm for the engine but I would have thought the gap should depend on the plug to ensure a good spark, but I'm not that knowledgeable on how things work.
