Aside from this, the only other part of this test mule that appears to turn heads is the fact that it’s dirty, but that's likely a boon to the changes that Mercedes made under the hood. Thanks to Mercedes’ recent engine roll out
that included four separate engines, we can expect the S550 Convertible to get AMG’s new twin-turbo 4.0-liter V8 to replace the thirstier 4.7-liter V8 in the previous car. The AMG S63 model will also ditch its larger engine, a 5.5-liter V8, in favor of a more powerful 4.0-liter twin-turbo V8 and both engines will be mated to Mercedes’ new nine-speed automatic transmission to wring out just a bit more fuel economy. Expect to see an official unveiling at the upcoming Geneva Motor Show.