All it does is it advances timing to produce more power....it only works on *some* motors (others run into so much KR that it actually causes power loss), I wouldn't even want to put a number to the power gain you might see because it will all depend upon your tuning, temperature, fuel quality, and driving habits
all this mod is doing is telling the PCM that the outside air is colder than it actually is...the PCM will then run a more aggressive timing curve due to the colder air-charge. this mod would be useless to anyone that has a programmer or LS1edit because you can advance the timing to suit yourself with those

 

ok thanks for the info. now i understand.