Here's the logic: Use only the best gas and your car will need fewer tune-ups and get better mileage, thereby paying for those extra cents per gallon.

Yes, says Martin: "The car runs more efficiently, burns better. With today's computers and everything being electronic, the better the ignition point, the better the fuel economy.

"Plus the car has less chance to knock and make noise. I run nothing but high test in everything I own."

Nonsense, counters Duchene: "The difference between 87 and 93 octane is so insignificant that you will realize neither better mileage nor fewer maintenance bills by buying supreme. It makes no difference unless the car is supercharged or it is absolutely specified that it needs higher octane.

"Buy the cheapest -- unless you're in Mexico, where the cheapest is closer to kerosene."

-- Text by Jay MacDonald, illustrations by Brandy Kesl.