It sounds like P.T. Barnum is alive and well, and selling spark plugs. To be effective, something like that would need to include a chassis dyno, or somebody foolish enough to ride on the fender and watch the color of the plug during highway operation.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!