I saw an ad for something called a Turbonator. It installs in the intake downstream of the airbox and it claims that its ability to swirl the intake air can improve horsepower and fuel mileage. I assume this swirling motion is supposed to reduce other, more detrimental forms of turbulence in the intake airstream. I'm not particularly concerned with boosting the HP of a minivan, but boosting the MPG sounds attractive. Has anybody else heard of this thing, and does anybody know if it works at all?