100 Octane VS 91 Octane
I've used two tanks of gas - one filled with 100 Octane and one with 91 octane.
I went to my favorite station that sells 100 octane unleaded VP racing fuel at a specialty pump for a fill up (6.499 a gallon)
Using 100 Octane I clocked 283 miles using 13.014 gallons = 21.75 miles per gallon (13.014 * 6.499 = $84.58)
Usine 91 Octane I clocked only 255 miles using 13.6 gallons = 18.75 miles per gallon (13.6 * 4.499 = $61.20)
The SRT was just not as crisp on the 91 octane (and what ever it is they cut it with for the "summer blend")
The price difference per fill up was $23.38 - but I gained 28 miles and burned about 1/2 gallon less with the 100 octane - so it actually only cost me $14.38 more to use 100 Octane fuel.