Styling-wise, the drop - top differs from the coupe by its obvious lack of a roof (to be replaced by a soft rather than hard top, happily) and the missing carbon side blades. (evo.co.uk)
Extra steel reinforcement tubes help keep the body rigid despite the lack of the roof. (automobilemag.com)
Drop - tops are heavier because of the strengthening required to compensate for the lack of a roof, and even with extra bracing their structural integrity is inevitably reduced, compromising handling precision. (evo.co.uk)