I understand that items like edge ez and comp increase fuel and hence horsepower, but what else do they do. What is the difference between the two, the comp seems to be for more wild apps where the ez seems to be for mild. I read about people stacking with TST or something like that, can anyone just fully explain the fueling boxes to me.

 

The mild fueling boxes plug into the harness between the MAP sensor and other sensors to "fool" the computer into sending more fuel to the engine, thinking it is required for those conditions. The way this happens is the box takes in the signal form the sensor and adds a precalculated amount to it before sending it on to the ECM/PCM.
The more radical fueling boxes, fool the computer into thinking the values from boost, etc. are within normal ranges so the EM/PCM won't set a code, but the more radical boxes tap straight into the VP-44 and make the duration of the primary fuel solenoid longer, pumping more fuel into the engine. This must be done because the more radical boxes excede the stock computer's ability to up the fuel, in other words, you can't "fool" the stock computer enough to get it to pump in THIS much fuel.
I'm not sure hwo the boost control on the Edge Comp works, but I understand it has a separate fueling and boost controls on it.

Chris