[Didymus]

Nearly all Tamiya products, especially their spray paints, are of very high quality. They are easy to use and produce excellent results. You can feel comfortable buying them.

As to getting all those shades, it's a matter of how finicky you are. It looks realistic to paint each mechanical part a different shade, but the difference between magnesium and aluminum is not important unless you are in a competition with extremely strict judging.