It's why I asked if "racing" was on the menu.
Shorter stopping distances: If the brakes you have are capable of locking up the wheels at the maximum speed at which you drive (and mine are) then changing the pads or the disks will not (unless there is fade) make any difference to the minimum stopping distance, which is a function of the co-efficient of friction at the point where the wheel is just short of stopping rotation.
Brake modulation: Unless you have no ABS or the ABS turned off, brake modulation is not an issue. Even the most skilful drivers cannot modulate brake pressure as effectively as does ABS.
Firmer brake pedal: For a fixed master cylinder cross section and power assist, it's a function of the pressure in the system and the elasticity of the system. Changing the cross section and swept volume of the slave cylinders could make some difference, but it would be marginal and it is not obvious, without doing detailed calculations, in which direction the change would go.
Less brake fade: Yes, absolutely, if you are driving in such a way that you experience fade, this would be an advantage.
So, for racing, where fade may be a problem, a useful mod. For the rest of us, I conclude that it is pretty much a complete waste of money? Unless of course it's a "pimping" issue? . . . :D
I should also say, that there may be penalties in other directions. Changing the unsprung weight is not without handling consequences.