As a Master ASE certified mechanic, I find that post chock full of lies. Even the king of mileage, the Prius only gets 51mpg max, the next best car that uses gas would likely be a Jetta TDI averaging 42mpg.
If a company made a regular gas powered car that got 60-80mpg on average during normal driving, the automotive world would be shouting it from the rooftops.
And in Europe where a gallon of petrol is over 6.00, they would buy them like mad.
Not saying GWBU is gonna change a thing in the world of fuel economy, just saying your post has very little factual info.