You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract Fastest Growing Car Brand in America? Buick After Years of Struggle, GM Brand Shows Signs of Big Turnaround By Rich Thomaselli, Published on August 16, 2010 15 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Become a Member Already a member? Log in.