Hey guys, the website may not be the clearest, but basically you buy the tuner and they install the proper program in it. So when you get the unit, u plug it into the OBD port of your my. Located just under the staring wheel. Then turn it on and follow the prompts. First, it downloads your mh old program, and saves it, then uploads the new program. Since the ECU (vehicle onboard computer system), controls everything, transmission is fed a new program also. One can change back to the original program at any time, and they suggest you do that if taking vehicle in for any engine work.
Hope that explains some of the questions. To me, the 10% mileage improvement was icing on the cake, as better engine and transmission performance was what I was looking for.
