I've never heard of this before, what does it excatly do for your car, restore defaults or something.

 

no it adds more fuel and increasing your redline (gm stage 2 i know does for sure), on my reflash it added more fuel and changed my shift points some for the charger since i was adding boost. it basically tunes your ecu in to fit the bigger injectors and the boost pulley.

 

this depends on the situtation. saying flash alone doesn't mean much if it isn't in reference to a certain situation.