You could use a scotch brite pad and some good spray paint (with primer) and get these looking awesome. Having worked in a body shop, I know this can be a good long term solution when done properly.
Nankang, Wanlis are cheap/low quality tires, but Kumho and Hankook tires are considered high quality tires. FYI - Hankook tires come standard on 2011 Volkswagen TDI.