Marc Muzzo and Karl Williams claim class championships in North American series. Full race report: http://races.ferrari.com/en/finalimondiali2017/news/challenge-na-2017-marc-muzzo-and-karl-williams-claim-class-championships-in-north-american-series/ Follow us on: Twitter @FerrariRaces Facebook @FerrariRaces Ferrari Since 1947 http://www.ferrari.com