I have played with it very briefly, and it does work to a degree. I had the intention to try it on a truck but did not go though with it. The reason is the idea of driving around with a gas tank in the engine compartment is too dangerous to me.
One good size accident, or a flash back, and you could catch your car on fire and possible worse. Personally i don't think it is worth the risk. I think you can get similar results with the same type of modification they use (super heating vapors) but using water/steam instead. Much safer and possible as good or better results
When you're one step ahead of the crowd you're a genius.
When you're two steps ahead, you're a crackpot."