The 512 is more streamlined compared to the 513. It has fewer panels, creating fewer lines on the shoe.
"This is a production picture from the Model Mid Sole Classic 512 It look like any other sole but has a hidden hieght increaser inside the shoe. Heel size on all the MST are 1 inch the rest is hidden inside the shoe. No slope inside the shoe and you will look taller by 3 inches"