NSX paint coating technology is special because the base material is aluminum not steel. Aluminum is an impossible metal to coat with paint, unless special priming steps are taken before color is laid on the surface.
Now, a complete repaint, that does not disturb the last factory gray prime coat, can be a "better" job than the factory. Why?
The NSX has some orange peel. The orange peel effect can be eliminated.
A smoother surface, of equal or better surface "toughness" than factory, can be achieved with proper technique. Indeed, paint layers needs to be thin and wet sanded by hand. The final coat must be hand buffed to remove the sanding scratches. The surface can be made mirror smooth, if that is your goal. Though modern machines make the job less onerous, it is still a manual process and that is why it can cost 15K.
Veterans of automotive refinishing will well remember the advantages/disadvantages of lacquer/enamel during those days when these were the two paints in use. Preparation and application of material techniques to achieve show car quality have not changed much, though the coatings have changed drastically.