The S 55 AMG (2001–02) was outfitted with a 5.4 L V8 engine while the later versions (2003–06) sported the same motor, but supercharged to a rated . The S600 (2001–02) was outfitted with a 5.8L V12 engine while the later versions (2003–06) sported a twin-turbocharged (or Bi-Turbo) 5.5L V12. The justification for having two models with the same power is that the S 55 AMG is sportier and more responsive, while the costlier S600 is more luxurious with a smoother ride. AMG phased out both the naturally aspirated and supercharged 5.4 L engines in favor of the new M156 V8 beginning in 2006, which was paired with 7G-Tronic. However, some enthusiasts were disappointed because the naturally aspirated M156 produces less torque than the supercharged M113K. For the Model Year 2009: M113 5.4 L "55" V8 models (naturally aspirated) SLK 55 AMG M113 5.4 L "55" V8 models (supercharged) G 55 AMG Previous 55 AMG models 1999–2002 E 55 AMG 2003–2006 E 55 AMG 2000–2003 ML 55 AMG 2003–2005 C 55 AMG 2001–2002 CLK 55 AMG 2003–2006 CLK 55 AMG 2004–2007 CLS 55 AMG 2001–2008 SL 55 AMG 2001–2006 S 55 AMG 2001–2006 CL 55 AMG 2005–2006 C 55 AMG 2001–2009 G 55 AMG "63" M137 6.3 L V12 The "63" badging was used on the short-lived 2001 S 63 AMG, 2001 CL 63 AMG and 2002 G 63 AMG. These were produced in limited quantities for one month and only offered through AMG to select customers in Europe and Asia, purportedly state leaders. The CL 63 AMG was the rarest C215 CL of all, and just 26 examples were built in November 2001 (51 plate), with some UK being and one for France registered in March 2002. These had a base price of £110,000 (~US$200,000). The G 63 AMG was the rarest W463 of all with just 5 examples built in September 2002 and sold in Germany at over €250,000 each. These are powered by a naturally aspirated 6.3L V12 producing . This engine is based on the M137 5.8L V12 used in the S 600 and CL 600, but the AMG variants have a larger displacement, a new management system, a new crank case and cooling system, weight-optimized pistons, and a new camshaft with greater valve lift and modified valves. of torque are available between 2500–5800rpm with a peak of at 4400 rpm while horsepower grows by almost