I havent bought in a while. Last time I did it was like $7/gallon for VP C-12 in a 5 gal drum. Fuel prices are VERY subjective.
As far as the sound..If an 9.5:1 pump gas engine is making power, it will be loud. In most cases, race fuel is the crutch engine builders lean on. The way to the max power is controlling the burn and maximizing pressures. Years ago, you had to slow down and cool the burn to develop high pressures. Now you can do it with fast burning fuels and the right initial engine design. For a bracket racer, fuel costs can mean a few days not racing if the price gets too high. Also, fast burns mean less timing, and less stress on the bearings. It's really a win win situation these days. I'd say as recently as 5-6 years ago, that was not the case.
