i agree with most of this, except "Now when tuning a car you must use a correct ramp rate on it.If the wrong rate is used the car will be out of tune."Running in the wrong mode(eg Shoot 6F) in a 4 cyl only changes the ramp rate. On the road, the engine sees 1000's of different ramp rates(different gears and hills)so a good tune with a good ems, will work in any mode. You need to remember that they are a diagnostic tuning tool, and DD's have tried to compensate for the variables to provide a level playing field in different conditions. We ran the two dynos side by side at powercruise, and took a car off one and put it on the other, and.5hp difference.