Our spies have managed to catch the 2012 Mercedes GL undergoing testing alongside the SLS AMG Roadster.

While the SUV/crossover is heavily disguised, we can see it will be larger than the current model and feature a bold front fascia with a massive grille that mimics the facelifted R-Class. This particular prototype also has AMG wheels and a high-performance braking system, which could indicate that it's a GL63 AMG or a standard model with an AMG performance package.

Engine options remain a bit of a mystery, but we wouldn't be surprised if choices include a twin-turbo 4.6-liter V8 with 435 PS (320 kW / 429 hp) and a 3.0-liter turbodiesel with up to 258 PS (190 kW / 255 hp). On the other hand, the GL63 AMG is expected to use a twin-turbo 5.5-liter V8 with 544 PS (400 kW / 537 hp) and 800 Nm (590 lb-ft) of torque.

As for the SLS AMG Roadster, it will feature a 6.3-liter (6,208cc) V8 with 571 PS (420 kW / 563 hp) and 650 Nm (479 lb-ft) of torque. Connected to a seven-speed double-clutch transmission, the engine will enable the drop top to accelerate from 0-100 km/h in 4.0 seconds and hit a top speed of 309 km/h (192 mph).

The SLS AMG Roadster is scheduled to debut at the Frankfurt Motor Show, while the GL will likely be unveiled late next year.

Gallery: 2012 Mercedes GL spied with SLS AMG Roadster

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