Maserati has just announced that it will premiere an even hotter version of the GranCabrio at the Geneva Motor Show next week. They are talking about the Maserati GranCabrio Sport which will pack more power thanks to an optimized engine and a more efficient transmission.
Powered by an all-alloy naturally aspirated 4.7-litre V8 engine mated with the ZF 6-speed automatic gearbox, the Maserati GranCabrio Sport will produce 450 HP (331 kW) and 510 Nm of torque which are enough to make the two-door cabriolet capable of reaching 285 Km/h.
Despite the power increase , the Italian company says the Maserati GranCabrio Sport is now 6 percent more fuel efficient, although the exact fuel consumption was not specified.
The Maserati GranCabrio Sport also benefits from a revised suspension plus drilled dual-cast brake discs, plus the exterior is now featuring a black grille with red accents, redesigned front side splitters new side skirts, and black painted alloys.
This new version is also debuting a new colour, the Rosso Trionfale, and the car will go on sale this summer.
The Maserati GranCabrio Sport price was not announced yet. 
Maserati press release :
The new Maserati that will debut at the upcoming Geneva Auto Show will offer more driving enjoyment thanks to an improved overall vehicle dynamics, more horse power, a more responsive and efficient engine and optimised gearshift response.
Modena, February 21, 2011. After stunning the world with the GranCabrio at the 2009 Frankfurt Motor Show, Maserati will use the 2011 Geneva Motor Show to take its grand-touring convertible to a new level of performance and handling with the GranCabrio Sport.
Conceived to give the GranCabrio a harder-edged model to sit alongside the GranTurismo S and the Quattroporte Sport GT S, the GranCabrio Sport uses a more powerful and fuel-efficient version of Maserati’s, all-alloy 4.7-litre V8, coupled with the ZF six-speed automatic transmission.
This naturally aspirated engine produces in this configuration 331 kW (450 horsepower) and has 510 Nm at the peak of its rich, thick torque curve. Maserati’s Friction Reduction Program has made the GranCabrio Sport’s engine more reactive to the driver’s most-nuanced inputs, while reaching a 6% reduction in fuel consumption. The top speed of the GranCabrio Sport is 285 km/h.
This six-speed transmission is equipped with the super-fast MC Auto Shift software and has been developed for the GranCabrio Sport directly from the transmission in the Quattroporte Sport GT S. The MC Auto Shift provides optimised gearshift response resulting in an even-greater engagement.
The handling has received attention, too, with an upgrade and revision of the Skyhook active-suspension system – now with a sportier tuning – and the adoption of grooved and drilled dual-cast brake discs.
Visually, the GranCabrio Sport is characterised by a more-pronounced dynamic look. This look begins at the GranCabrio’s distinctive nose with a black grille and a Trident with red accents. The headlights now have a black look with white sidemarks, while front corner splitters and the redesigned side skirts are both body coloured. The GranCabrio Sport also debuts a new body colour for Maserati: Rosso Trionfale inspired by the red Italian national colours used on 1950s racing Maseratis – in 1957, Juan Manuel Fangio won his fifth F1 World Title at the wheel of a red Maserati 250F.
The GranCabrio Sport will be on sale in all of Maserati’s 62 markets starting from summer 2011

Source: Maserati