Since the dawn of the automobile, people have been pouring all sorts of nostrums in their tanks (and crankcases) to achieve more power or better mileage. For the most part they've wasted their money. I'm sure in some cases they've damaged their engines. IMHO nothing works better than name brand gas from a station that pumps a lot (so the gas is fresh with less chance of contamination), and regular oil changes with the factory recommended oil grade.