Bugatti will introduce an open-top version Veyron Grand Sport producing 1200 HP at this year’s Geneva Motor Show. This new variant will be called Vitesse and is basically a mix between the roadster and the Super Sport. 
Its power comes from the same W16 engine delivering 1,200 HP and 1,500 Nm of torque found in the Super Sport, which means it has larger turbochargers and intercoolers than the ones on the regular Veyron.
So in order to perfectly accommodate the considerable amount of power the Bugatti Veyron Grand Sport Vitesse is also featuring an adapted chassis with Wolfgang Durheimer, Bugatti President stating that "We gave our all to transfer the achievements of the Super Sport over to
the Grand Sport, thereby turning open-top driving itself into an
extraordinary experience at high speed".
He also justified the company’s actions by saying that "The rapid success of the Super Sport convinced us to increase the
performance of the Bugatti roadster. Once again our engineers worked
hard to demonstrate that Bugatti is able to constantly redefine the
boundaries of what is technically feasible".

Source: Bugatti