I've seen these Tornado style intakes advertised on TV. In their demostration they use two, 2 liter soda bottles connected together at the threaded end, with one filled with water.
First they would simply turn the one filled with water upside down (like an hour glass) and let the water dribble into the bottle on the bottom.
Then they would turn it upside down again, only this time they would shake the bottles (in a circular motion) to get the liquid spinning like a mini tornado, and the top bottle would empty itself much faster.
Using this principle of hydro-dynamics, they imply that their product will spin the air much the same way to increase the amount of air passing thru your intake tubes.
Now I have no scientific evidence that this theory works or not, but common sence tells us that air starts moving pretty fast in a swirling motion of a tornado.
If there was some way to actually get the air to "swirl" in the intake tubes without installing one of those "tin" blades (that actually cut down the CFM) maybe a tiny "Ram" effect could be created.
But it seems to me, any benefit would be foiled as soon as this fast moving air (turbulent or laminar) hits the air filter. So why bother?