Hello, Please dont laugh when I ask this question!

But what is re-mapping and what does it do?

 

Do you know what the ECU is and what it does? your changing the OE (standard) map on your ECU to a tuners one, often you will get a substantial gain in performance, better MPG figures, and things like fueling checked to make sure all is well, i even got diagnosed with a fooked headgasket once