Simple resistor mod. Essentially your IAT (Intake Air Temp) sensor is a resistor that as the temperature of air changes the resistance changes allowing the computer to get a reading of the actual temperature of air being drawn in.
When you install the resistor provided it tricks the computer into thinking the air is colder than it actually is therefore telling it to add more fuel to the mixture.
Not sure I'd be trusting them to figure out which resistor you actually need. And I'm not sure i'd try it on our cars. (someone else that's more knowledgable in the SC'd field can chime in)
