I have read that resistor spark plugs can give the magneto a hard time. I would like to replace my standard plugs with iridium plugs, but the only equivalent is NGK BR7EIX a resistor plug. Would this be OK or would it lead to mag failure? I have seen on Youtube a way to convert resistor plugs to not resistor plugs which entails heating the plug, unscrewing the top and removing the resistor and substituting a length of copper wire. Has anyone actually done this?