With only plan taper of the roof,the Bugatti ends up with a fairly enormous wake.But it will be good for directional stability,like the transom of a ship.
On the internet,there is a photo of the Veyron crossing a dry lake bed at speed,and you can clearly see the disturbance of the air behind the car and it's wing.Dramatic!
Safety at 258-mph overshadows drag reduction.
