whats the best brand of gasoline around you? here, its Amoco or Texaco. gogas has really been horrible lately, as has the kangaroo stations' gas (ive heard they get it from gogas). anyway, since gas quality has gone down lately, can anyone suggest an additive that'll make it burn better? midgrade makes my truck ping at WOT or when i float the throttle, and driving a yukon 100 miles daily is not conducive to running 93 octane. anyway, i dont really feel like eating a piston, so any ideas on an additive?