I did a comparison of plugs before and after, and before the plate, #5 and #6 were running -mega- hot and lean, much more worn than my other plugs. After the plate, the same plugs run super rich, and I noticed a decent ammount of carbon on the suckers but they were still firing, not fouled. The plate does what it's advertised to do, and I did notice a reduction in KR. I think a modified doghouse might work better but it's significantly more $. The bang for the buck on the RJCPP is awesome, imho.