Any plug that's not double-platinum will have problems eventually. For me it took four months for splitfire plugs to begin to show signs of premature wear (hesitation at 3000+ rpm and 80+ mph). I switched to Autolite APP764 with no problems since (over one year now), but someone (DemonSVT?) mentioned that there is another Autolite plug that has the coating you're referring to. I believe the APP764 does not, but I'm not sure.
