The problem with a colder plug to 'add some spark' is the risk that the plug is too cold to burn off the tip deposits in cruise/idle mode. It then misfires....right when you want max spark energy.
The object is to bring the tip temp to over 400* C & keep it there, where it self cleans; max temp should be 850* C, so there is a 400+* C [ 720* F ] working range.
