Can't open the link - but it sounds like you are talking about a Tornado or some passive air swirling device like it.
If it is not passive - as in it spins - it is a joke.
If it is passive - some swirl devices can help some cars IF the current air passing the airflow/MAP sensor is not ideal. This is often the case when a factory air box is removed and an open pod filter fitted - it completely changes the airflow direction and pattern and this can affect MAP sensor readings.
I had this problem on a turbo car - it ran too lean to safely run high boost. For a joke I fitted a siwrl unit before the throttle body because a tuner had them and said I should try it. It straightened the air and gave much better readings - which richened the mix up considerably and that enabled me to run another 4lb boost on same timing.
In other words - an air swirler can cometimes correct a problem - but it will not ADD 1hp to a well set up engine that is already getting correct MAP sensor readings.
I'd be surprised to see any gain in a stock car as the factory would want shooting if they allowed partial airflow to pass the MAP sensor and give false readings.
