Originally Posted by Quicksilver

DR. Bill Wattenberg dosen't think so.

Consumer Tip: Save your gasoline money if you are buying premium gas. It's unnecessary to use it unless your engine pings. Use regular instead.
Dr. Bill Wattenberg, Phd., Physics, KGO radio talkshow host.

Here's another vote for the same line of thought.
http://tinyurl.com/23bc9

Apparently Octane ratings define gasoline.
The octane rating of gasoline is shown by a number on a yellow sticker on the gasoline pump, usually ranging from 87 to 93. While there is no national definition of fuel grades, the Society of Automotive Engineers (SAE), which sets standards for the auto industry, defines regular as having an octane rating of at least 87. Midgrade is defined as an octane rating of at least 89; premium, at least 91.

In most places, a service station legally could use "premium" to describe any octane rating it chose.

The SAE definitions were created in response to service stations that sold only two grades — 87 and 89 octane — and called their 89-octane gas premium. That misled some consumers.

To avoid confusion, owner's manuals usually recommend an octane number for the car or truck, rather than relying on the terms premium, midgrade and regular.