It's a popular misconception that premium gasoline is "better" when in all truth, it has absolutely nothing to do with the quality of the gas. Pay no attention to the word "premium" because it is nothing more than a gimmick that the oil companies have brainwashed the masses into believing it means "better" just so people will spend more money when most of them don't have to. The real difference between regular and premium is the octane rating. You've seen the yellow stickers that say 87, 89, 92 (85 or 86 in higher elevations and up to 95 in lower ones). Those tell you the octane number of the fuel. The higher the octane, the more resistant the fuel is to igniting under higher compression, which is what most high performance engines tend to be. High octane fuel exists because putting regular fuel into a high performance engine with high compression means the fuel can ignite prematurely causing detonation which can damage or even destroy the engine. Conversely, high octane fuel will not hurt a normal engine, however depending on the design and application of the engine, it could potentially run worse and/or get worse mileage because the main drawback of high octane fuel is that it burns slower and less completely than regular gas, and all you would be doing is wasting your money. It is always best to use the fuel specified by the manufacturer for your vehicle.