No, I think these chips actually work. I think they did a show on Speed Channel about it a while back. But it only works on stock NA cars I believe. It manipulates the a/f or some shit and gives it a lil more achievement. It's kinda basically a cheap SAFC I guess.
So once you start modifying your car, this chip is useless.
Some of my friends have old domestics or big trucks and always talke about, "hey, i got intake, exhuast and a chip and I have an extra 100hp" or something like that. I am sure this is what they are talking about, but like many things for sale online or on TV, where is the real evidence? If an AFC only gives 10-15whp improvement then on our 3L engine then perhaps a 25hp spike is possible on a small block; regardless, leaning out the car this way is probably not the best idea, nor is it proven.
its just a resistor which does trick the car to get more air. it does work. your supposed to jam it in the maf clip, but i dont see how any modded car should use it. i mean most us cant take a chance of messing with the air/fuel? you know? maybe if its bone stock.