[video=youtube;UHAUsGlfbx8]http://www.youtube.com/watch?v=UHAUsGlfbx8[/video] (mostly the last suggestion)
I would assume it's illegal because of vapors from acetone. edit: maybe not, IDK "Exposure can occur if you live near a landfill site that contains acetone, near busy roads, or near other facilities such as incinerators that release acetone emissions." http://toxtown.nlm.nih.gov/text_version/chemicals.php?id=1 I work with acetone all day though, and it's kind of nasty stuff. It is flammable, so it might be more dangerous for accidents. There was a mythbusters about blowing up a gas tank, and they decided it was just too hard to get the right vapor levels. Perhaps with this, it would be very easy for a car explosion?
I think you should try to find a mechanic friend. I have heard of people burning hydrogen in their car with gasoline and then fucking up their pistons.
I've tried all of those along with others and have had so much success that every morning I'm able to go out and drain out 3-5 gallons of gas out of the tank that wasn't in the there before I went to bed the previous night.