Yeah, its 91+ recommended, but 87 required. You can use either, but will get a little more horsepower and fuel economy using premium. As the price of gas rises, the differential between regular and premium tends to be 20 cents a gallon, and its fixed. So the more the prices rise, the "cheaper" (relatively) premium actually becomes.
I notice more pep on premium and the mileage difference for me on all city driving is 15mpg on regular 87, and around 16.5mpg on 93. Since premium is less than 10% more expensive than regular, its worth it to me (even not considering the power difference, which for conservative drivers might not be noticable).