In Forza Motorsport 6, which of these track-exclusive cars was NOT featured in the game, either originally with the game or added as DLC?

The Aston Martin Vulcan was not featured in Forza Motorsport 6 as a track-exclusive car, either originally with the game or added as DLC. It could be because the developers may have decided not to include this particular car due to licensing issues, limitations of the game's engine, or other strategic reasons.