(http://media.il.edmunds-media.com/mercedes-benz/m-class/2012/ns/2012_mercedes-benz_m-class_actprf_ns_72211_196.jpg) Mercedes-Benz will expand and upgrade its Tuscaloosa plant, which has just begun building the redesigned 2012 M-Class, in preparation for the next-generation GL-Class crossover, as well as the 2014 C-Class sedan.