There was a recent Popular Mechanics article that covered the Tornado device, a clone of the Tornado, sold on Ebay, and several other items, like the magnet you place on the fuel line.
The results read like this.
"Both devices reduced peak horsepower by more than 10 percent. The Twister increased fuel consumption by more than 20 percent. The Tornado fuel saver provided no significant change."
Now I'm sure your results may vary, but from what I know, you want a clean undistrubed pulse of air, on the intake stroke. Even if it was "swirling" it would be disrupted every time the intake, takes in air. Just like passing your hand under the faucet while it's running. If you put your hand back by the exhaust, you'll notice it's pulsing, not flowing. I feel it would be impossible to make 6 seperate mini tornados all going with some sort of regularity and consistancy.
Get an intake kit from K&N, you'll be better off in the long run.