the product makes sense, the increase in mileage does except the fact that in one post they say the resistor wire only works for initial acceleration not cruise speed,
although if your opening the throttle that much more it may save mpg if it is actually providing more fuel in that range,. but 5mpg? I guess if they have a lot of starts and stops?
I'd like to see it it myslef on a dyno with gas analyzer to be sure there would be no damage fromrunning to rich or lean