The Tornado does not work..plain and simple. First, lets examine the obvious. If such a cheap device could give even a 2% increase in fuel economy the auto makers would pounce on it. Imagine meeting CAFE standards without having to spend millions in R&D. Obviously, since better fuel economy is in their interest and since they show NO interest in this device, one can surmise that they don't believe it works.
Second, with modern fuel injection, mixing problems are a thing of the past. In a carb set up, fuel is streamed in a course squirt from the jets into the venturies. There it mixes with the intake air and atomizes before being drawn into the combustion chamber. Long plenums, rough surfaces inside the manifold and polished intake ports all help to mix the gas/fuel mixture better so that it burns with greater efficiency. In such a case, a Tornado device "might" help unless it restricted air flow in which case it would reduce power rather than boost it. However, in the case of modern engines with electronic fuel management and port injection, the gas is as atomized as it is ever going to get. And the air flow is monitored to get the ideal fuel/air ratio. Thus, the Tornado won't to squat.
Third, have you ever heard of any racers using this device? I didn't think so. The reason is plain and simple. In a game where winning is measured in thousandths of seconds and where the slightest edge can mean the difference between taking home the money or going broke, these guys use what works and junk the rest. Since they don't use the Tornado, you can again surmise that it doesn't work.
Last but not least, have you ever wondered why the makers of the Tornado don't have lab tests to back up their product? I don't mean guys they hire to do biased, a-priori investigations but rather independent, nationally recognized labs such at those run by Consumer Reports or one of the automakers? It's because they won't get the positive results they need to sell the product. In a controlled averment where human input is removed, the Tornado just won't work...period. So you ask, why do some "satisfied customers" report such an improvement? Well, my guess is they subconsciously drive better because they are so intent on seeing what improvement they can gain through this device. If you pay attention to your driving and drive smarter, you will see an easy 2% increase in fuel economy, perhaps even as much as 10%.
So, in conclusion, the Tornado does not work. Save your money. Or, send your money to me. I do work but I get paid far too little and could use more money. I won't help your gas mileage any nor will I make your car run better but shoot, I will spend your money with the same enthusiasm the guys at Tornado do and I'll not lie to you to get it.