The C-Class is the smallest sedan Mercedes makes. The 5.5L V12 engine from the S-Class is one of the largest engines the company makes. BRABUS decided that the two needed to come together. Also decided was that the big old 5.5L V12 was too small, so it was bored out to 6.3L. 

This new powerplant makes 800 horsepower and is limited to 811 ft-lbs of torque, because there wasn't a transmission available that could handle the engine's 1,047. This sends the Bullit from 0-60 in 3.7 seconds and on to a top speed of 230mph. That's one hell of a C-Class.

[via Spiegel Online and the wonders of Google Translate]