Pure Metal Silver is actually two separate BMW color coats before the clear coat: Glacier Silver is the base coat, followed by Pure Metal Silver and then the Clear Coat. According to BMW, the Pure Metal Silver paint costs 40 times as much as the Glacier Silver Paint.
In addition, Pure Metal Silver takes a lot longer than other Individual paint jobs because the surface has to be much smoother than for other paint colors. The total labor involved is much more than for other Individual paint colors. All of that is reflected in the increase price of the option.
In the end it's all a matter of personal preference.
