What would happen if we used regular fuel rather than the premium? If losing horsepower is all it is than, it may be worth the downgrade with price of gas these days.

I just read an article that stated this;

With prices already over $4.00 a gallon, premium gasoline is a hard sell these days. But a lot of drivers think because their owners' manual recommends premium, they'll get better fuel economy if they stick with it. Really, they're paying more money for nothing.

Even cars for which premium is recommended won't suffer with regular fuel. Modern engine technology comes to the rescue again. When sensors detect regular instead of premium fuel, the system automatically adjusts spark plug timing. The result is a slight reduction in peak horsepower - really, you'll never notice - but no reduction in fuel economy.