>Kinda figured as much, but my experience is only with Texas. Yeah, I've often wondered what makes mid-grade worth 25cents/gallon more than regular and 'premium' 15 cents/gallon 'better' than mid-grade. But then again, one of the most expensive Shell stations in Houston is the one right outside the Shell refinery. Go fig

My understanding is that nothing makes them more expensive, just that the fuel companies can get away with it. OTOH, you do need to use the grade recommended for your car to get the best performance. Engines are tuned to a particular octane (or, probably more likely, range of octane).

Tamar