First hand experience ... avgas has a different specific gravity than regular pump gas because it has to work at high altitudes. Subsequently using even a 10% mixture of avgas will necessitate a float adjustment. So that's fine and dandy as long as you always run whatever mixture you decide on. BUT, if you ever change the mixture and don't adjust your floats, the car will run like absolute CRAP. Personally I didn't see any benefit and it was a big hassle.