Another alternative to running octane boost is running a high octane unleaded racing fuel. There's a station not too far that sells the VP 100 octane from the pump. I think it's going for 4.99 a gallon currently. A couple gallons of this mixed with the 91 octane brings up the average a bit. However, for daily driving, this could get expensive! When I was in Louisiana last summer, I noticed that they had 93 as their premium... and it's cheaper than here! They always find a way to rip us off here with an inferior product.... grrrr