I’ve been using e3 spark plugs for years now in my vehicles. Got this one for a 3 HP minibike (motovox), and as with vehicles it made a huge difference in the way the bike runs. It runs much more smoothly and has a noticeable improvement in throttle response. I will stress also, the improvements are not due to “an old plug versus new one”. It is more due to the actual spark plug: these are simply one of the best spark plugs you can use.