Forza Motorsport 5

As you progress through the game you will need to complete championships - this is in career mode - you should get this naturally as you play the game on route to earning gold medals

If you play Career, and finish all the championships in order, plus the bonus races, starting at sport, you should unlock this after finishing the last championship under "Class Competition", you should also unlock Golden Standard(Earn 400 gold medals in Career Races), a race short of getting this if you get gold in every event.
Sport Compact(6 championships) (100 gold medals), Sport RT(6) (102),Grand Touring(3 (54),Exotic(3) (51),Class Competition(7) (94/98 with bonus races)