Thunderthud, first I want you to know that I am not picking a fight....but I feel compelled to mention a few things you have said that I have to take issue with. Please, if you can substantiate your claims do so, I have no problem admitting if I am wrong on anything here. I am not aware of any FAA regulations that prohibit dispensing aviation fuel into plastic fuel jugs. Please cite the official FAA regulation number so that I may familiarize myself with it. It IS however illegal in most areas to dispense fuel directly from an airport fueling facility (truck or fuel farm) into vehicles for street use. Why? Because the fuel price has not had the applicable State and Federal road use taxes added since the fuel is intended to be burned in aircraft. I believe AZMike when he says that he can buy avgas from the pump because it must have the state and federal taxes added to the price if the gas is sold in that fashion.
Also, I am not aware of any "fire retardant" added to any blends of Avgas. I know there was some experimenting done by the FAA at the cost of many millions of dollars with adding an expensive additive to Jetfuel (high-grade diesel) to reduce the volatility but that turned out to be a huge flop. (They filled a passenger jet with it and crashed it intentionally to see what would happen, they got a HUGE fireball).
Avgas by nature has a lower volatility than regular automotive type gas mostly because it's Octane index is higher. Octane is a measurement of a fuel's ability to resist detonation or the tendency to ignite before it is "told to" by the spark. I will agree the chemical composition of aviation fuel is quite different than other fuels to suit it to it's intended purpose and wide range of operating conditions, but that doesn't necessarily mean that it is ill suited for use in high performance engines of many different types.
It used to be that at some airports there were two main grades of avgas available, as far as I know only the 100LL (approx 100 octane, low lead) version is still available it's blue. The older type (the good stuff) was 100/130 (approx 115 octane, lot's ‘O lead) and was green. The 100LL has lead in it still so do not put in in anything that has a catalytic converter if you want the converter to last very long (the lead bonds to the chemically treated catalyst plates and over time neutralizes them, not good for your brand new Corvette). There is a commercially available aviation fuel additive available that actually binds to the lead molecules converting them to a harmless inert by-product that is harmlessly passed through the engine and out the exhaust pipe. The older engines were designed to be run with large amounts of lead which actually helped to lubricate the valves and guides, however the primary purpose for the lead was an inexpensive way to boost the octane rating.
In case you are wondering why I claim to know these things, I worked at the "Ogden Jet Center" at the Ogden Hinckley Airport (OGD) for three years as the Head Lineman in charge of fueling a fleet of Jets and hundreds of light single and twin engine aircraft (great college job) and am also a private pilot. Most of what I just mentioned I learned from the owner of the Ogden Jet Center, a retired Airforce Colonal(sp) who flies his own personal fleet of antique Vampire fighter jets. I may be wrong, but that would mean that he (and many other knowledgeable pilots) are also wrong and I honestly doubt it.
While working, very often I sold avgas to people that were planning to use it in Snowmobiles, Boats (professional racers), ATV's, Cars (built engines with higher compression), Lot's of Harleys and even chainsaws (professional tree-cutters claimed that without the avgas their saws would vapor lock). These people all felt that the Avgas was well worth the high price and kept coming back week after week so it must have been doing something for them. I have yet to run 100LL in my piped Scrambler, but I think I will give it a try to see what happens.

Whew!!!!!! My God I am long winded and I apologize for that, it's just not that often that I am able to use some of that obscure information that rattles around in my head. Hehe

Matt ‘99 Scrambler 400 RCR Stage 1 mods, ‘00 Trailblazer