It does not take longer to start a race, as the loading time before you get to the pre-race screen is much shorter now. Before 2.0 you had to wait for both the track and the AI cars to load before getting to the pre-race screen. Now the track is loaded first, then the AI cars are loaded while you are changing driving options in the pre-race screen. Though I am not sure if it loads the AI cars while you are in the car setup menu.
