I think it's funny that people pick on the M156 engine because it's labeled as 6.3 liters when yes, it's really 6.2. There's nothing else to pick on, I guess. Torque is torque and whether a 6.2 or a 6.3, one thing the M156 has is bucket loads of torque. And it's a NA motor.
fwiw:
"Although it displaces 6.208 liters, the engine will be marketed as the "6.3" to comply with German car tax laws, which require them to be rounded up to the nearest 100 cc." In addition, AMG wanted to pay homage to the famous 6.3 of the past.
If truth in advertising upsets anyone, then just take off the badges and then you've got a whatever liter AMG.
http://www.eitechnologygroup.com/gal...age_full/1135/