What does Premium Gas do?
Premium gas, which usually has an octane level of 92 or 93 (compared with regular's octane level of 87), is designed to prevent knock on cars with high compression ratios. The compression ratio is the total volume inside the cylinder that is displaced when the piston moves. If you use low-octane gas on a car with a high compression ratio, it's more likely that the gas will ignite prematurely, causing your engine to knock and rattle. A mild knocking isn't necessarily harmful to your car, but it certainly isn't something you want. Heavy knocking could damage your engine.

What Cars Require Premium Gas?
The majority of cars are designed with a lower compression ratio, so low octane gas is more than adequate to power the engine without producing knock. In fact, few cars require premium gasoline these days. Usually it's just the luxury cars. The best way to find out what your car requires is to look in the owner's manual.

If your car requires premium gas, then you need premium gas. Your car has a high compression ratio and, moving to a lower grade will likely cause knocking.

If your car does not recommend premium gas, then you don't need it. In fact, if your car doesn't say anything about premium gas usage, all you'll be doing is dumping more money into your car. Premium gas will do nothing to increase the performance of a car that wasn't designed for it, so don't waste your money. It may sound like you're giving your car the good stuff, but it doesn't notice the difference, and neither will you.