This car features the new AMG Mercedes-Benz 5.5-litre twin-turbo V8 - a similar unit to the one used in the just-released Mercedes-Benz CL 63 AMG. There's currently two different AMG versions of the SL: a 6.2-litre naturally-aspirated V8 (SL 63) and a top-spec version with a 6.0-litre twin-turbo V12 (SL 65). This new SL 55 will replace the SL 63 version.
It's unknown if there will be any significant power changes over the existing 6.2-litre V8, although reports suggest the figures will be very similar to the 386kW and 630Nm of the current SL 63. Torque, however, from the 55 is expected to be slightly higher with the help of twin turbochargers.
Other major changes include vast revisions to the look of the new car. From these images, which show a test mule in its early stages, the body of the new SL 55 will adopt the new Mercedes-Benz design language, particularly around the face. From the front we can see the new car will showcase a low front chin and somewhat aggressive side vents for the AMG special, and incorporate that new, more pronounced upper centre grille.
The rear will incorporate a new spoiler, although it is a bit hard to tell just how large it will be under all that black covering. It might get an electronic pop-up-style wing or airbrake for added downforce, however, it is too early to know for sure. The AMG will feature traditional quad outlet exhausts, in a square-ish design.
The 2012 Mercedes-Benz SL 55 AMG is expected to go on sale sometime next year. We'll be sure to provide more concrete details on its debut as soon as we can.