M156 head-bolt and lifter failure risk

Every CLK63 BS uses the early M156 V8, whose torque-to-yield head bolts (and related lifter/oil-leak issues) can, in the worst case, take out the engine. The community is split on how real the threat is: some treat a preventive top-end rebuild with ARP studs as near-mandatory, while shop insiders and a dealer mechanic argue documented failures are rare and typically announce themselves with cooling or leak symptoms first. …