The first pic on the thread looks like one of the pre-production W204 mock-ups that were leaked to the press quite some time ago.
All trim levels of the production W204 C class will share primary sheetmetal.
Avantgarde models recieve lower body aerodynamics, AMG wheels, revised sport grille with star on front.
Elegance, and Classic models delete the lower body aerodynamics in favor of a more conservative look, feature traditional grille design with star on hood, and wheels that are more luxury oriented in design.
Here you can see the production Avantgarde next to the production Elegance:
http://www.worldcarfans.com/news.cfm/newsID/2070118.005/pageview/photo/photo/Mini7/page/1/country/gcf/mercedes/new-2008-mercedes-c-class-revealed