Champion = junk I discovered this the hard way 35 years ago as a kid with a new-to-me Honda Accord hatchback. It ran like **** when I bought it. I installed the NGK plugs recommended by the local dealer and it ran like a top. I've turfed Champion plugs in everything from cars to lawnmowers to airplanes. Champion remains a great American brand trading on the glory of their achievements of nearly a century ago, rather than a company that lives up to its advertising and brand standard by manufacturing products worthy of the name. Champion is just a name any more, not a quality or performance standard.
Tempest it is, until I get to the point of having two P-Mags, then it will be NGK.