Auto Parts: Tornado, increase hp, gas mileage

Question
Do you know if the Tornado really works?  You know the thing that they advertise that is suppose to save help your car save gas and increase HP. I have read a few articles about it...some say it does and others say its a waste of money. I have a 1999 Toyota Sienna and am trying to save some gas mileage with his device.

Answer
They're junk. Everything i've read says they don't make any gains and sometimes decrease power. The best thing for mileage is a good tune-up and watch your tire pressure. Also don't drive it like a race car, it's a truck. The lighter your foot is makes an incredible diff. in mileage.