Car and Driver road test numbers for the W218 2012 CLS550 with the M278 twin turbo V8 almost equal previous gen CLS63 AMG
The new M278 twin turbo V8 powered Mercedes vehicles are going to have a lot of the previous generation 63 AMG owners scratching their heads when they can't pull away from them at a stoplight. The new 550 models are just about as fast as the previous M156 based 6.2 liter naturally aspirated V8's. Case and point, Car and Driver hit 12.8@112 in the 2012 CLS550. In the 2007 CLS63 AMG, they hit 12.6@114. Oh, the new CLS550 is also lighter by almost 200 pounds than the previous generation W219 CLS63 AMG.