Not received a HIPA but almost bought some bootleg NGK's off EBAY until I read that bootleg spark plugs were on the market. I had a lawn boy given to me that would not keep a constant RPM. The previous owner had replaced the governor assembly and had installed a new spark plug. One of those plugs with a "special" shaped electrode for better spark. I checked the governor and it was ok and the plug was clean but no even RPM until I installed a Champion plug from one of my other Lawn Boys. Long story short use the tried and true part.