Two soft-top SLS AMG Roadster prototypes caught undisguised on a ferry between Germany and Sweden.

This spy shot of the upcoming SLS AMG Roadster was captured with a camera-phone by an apt automotive pupil on the Stena Line ferry going from Germany to Sweden.

[More photos at source.]

The photo shows two soft-top SLS AMG Roadster prototypes sitting idling in the ferry's bay. Spotted alongside the prototypes were also an ML-Class Mercedes-Benz, an SLS AMG Coupe and an Audi R8 Spyder - likely for benchmarking the SLS AMG Roadster.

It's interesting that AMG engineers chose the R8 Spyder as the SLS Roadster's arch-competitor.

The SLS AMG Roadster will not come with the gullwing doors of the standard SLS AMG for the obvious reason that the car is a cabriolet with a retractable roof. The SLS Roadster will feature AMG's 6.3 liter (6,208cc) V8 with an output of 420 kW (571 PS / 563 hp) and 650 Nm (479 lb-ft) of torque. That makes for a 0-100 km/h sprint time of just 4.0 seconds and a top speed of 309 km/h (192 mph).

Gallery: Mercedes SLS AMG Roadster spied completely uncovered

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