The engine was designed to be a naturally aspirated racing unit, and is also used in a number of high-performance AMG-badged Mercedes-Benz models.

The engine, however, has been uprated to produce 518 hp (525 PS; 386 kW) and 465 lb⋅ft (630 N⋅m) of torque in the late S 63, E 63, SL 63 & CL 63 models [1].

Applications: In 2011, a class action lawsuit was filed in United States District Court in New Jersey against Daimler AG, Mercedes-Benz, Mercedes-AMG for alleged defects in the M156 engine contained in AMG vehicles built in 2007–2011 model years leading to premature wear.

The plaintiff claimed the combination of cast nodular iron camshafts and 9310 grade steel valve lifters contributed to the premature wear, but the defendants had known about the defect since 2007.

In November, 2012, litigation came to a halt when the New Jersey District Court dismissed the plaintiffs’ first amended complaint for lack of standing.