The supercharged E55 and naturally aspirated E63 are constantly compared: E55 partisans cite the M113K's superior durability, low-end torque, and freedom from the head-bolt issue, while E63 advocates revere the M156 as one of the all-time great NA V8s. Preference is genuinely split, with some multi-AMG owners preferring the 63.
E55 (M113K) versus E63 (M156): character and reliability
Mercedes-Benz E55/E63 AMG (W211) · mechanical