Seems to me it would be a zero gain device. Air is a fluid, and will always follow the path of least resistance. With the stock box still pulling in hot engine air directly, I dont understand how you would expect it to pull cold air in down a 2-2 1/2 foot tube at the same time. Souldns like you'll just add a few pounds of plastic to an already noseheavy car.
Just my opinion. I would want to see real results, conducted by an independent lab before I spent any money.