Regarding the engine, it has about them in general is not known. For information - the engine compartment has the AMG V-8, the volume of 6.2 liters., Which produces 571 hp (420 kW) at 6 800 rpm and maximum torque of 650 Nm at 4 750 rpm. It is possible that this engine under the hood and a roadster. However, Mercedes SLS AMG Roadster 2011 can receive the V-10 engine, with an output of between 550 ... 650 hp
By the way a week ago, the company reported a Mercedes that have plans to develop an electric version of SLS AMG. According to Mercedes, the car will be faster than the Tesla Model S, acceleration to the first «hundreds» less than four seconds, with the same unit V-8. This innovation should appear at the coupe, which can later be also on the roadster.
Taking into account that the coupe debuted at the Geneva Motor Show in 2010, the convertible with the roadsters may appear even later.