NGKFR7BHX-S Spark Plug NGK Ruthenium HX Spark Plug

I purchased these, after I looked in to the technical data, to see if there was a scientific base to their claims. After fitting them in, I took it for a drive. Warming up the engine on tick over first, proceeded to take the car out of the garage. I noticed, touching the accelerator slightly, engine revved so easily, whizzed like an electric motor. So much more responsive than before. After a 25 mile or so drive I also noticed a couple of things they have not claimed; Like I said, it revved so easily, engine seemed more dynamically balanced, (it must have been because of more equalised ignition pressures within the cylinders).There was definitely more power available. After parking the car back in the garage, I glanced at the petrol gauge it hadn't moved, proceeded to tap on it several times, thinking it was stuck. I decided to look at it another time and switched the engine off, the gauge dropped to zero, obviously it wasn't stuck.This was the most significant thing, the fuel consumption went down so significantly. I do that journey very often and I know how much petrol the car used to use. And the corresponding deflection on the gauge needle. Another thing I noticed, the engine ran 5.0ᵒc cooler, which is big bonus, as our average summer ambient temperatures in this country is around 30ᵒc. On cars with "remapped ECU's", it will be much harder to resist the temptation to "rev it up" through the gears.Francesco.