[s-cars] Fuel Brand Comparison

[Jason Butler]

Has anybody in the Denver area done a comparison between different brands 
of fuel?  I know with my 5ktq we get better gas mileage with Diamond 
Shamrock than with many other brands, same goes for my 90 quattro 20V.  But 
when I use Diamond Shamrock in the S4 it tends to be a bit sluggish under 
boost (ie it tends to knock I am guessing).  So I was just wondering what 
brand poeple tend to use in their cars.

On another note where is the best place to get Toluene in the Denver area, 
both in small quantities and large?  I went to Sherwin Williams today and 
spent $13.50 :(  for a gallon to see if my sluggishness is just the timing 
being dialed back due to crappy fuel making the engine knock.

Jason