On the twin-turbo M157 G63, sellers and buyers treat resealed timing covers as a known service item, and pre-purchase inspections specifically scrutinize turbo oil feed lines, valve-cover gaskets and rear main seals. The consensus is that the higher-output biturbo demands more care than the M113K, framed as a normal pay-to-play tradeoff for performance.
M157 biturbo (G63) maintenance: timing-cover reseals and turbo lines
Mercedes-Benz G55/G63 AMG (W463 2004-2018) · mechanical