You're scrolling AutoTrader at 1am and there it is — a W212 E63 AMG, hand-built biturbo V8, sitting under $30k with 80,000 miles. The listing photos look clean. The exhaust note in the walkaround video hits different. You start telling yourself it's depreciated enough, that the previous owner already ate the loss so you don't have to. That's exactly how it gets you. The M156 in the pre-facelift cars has the headbolt failure that Mercedes quietly revised but never recalled. The M157 in the later ones? Better, but those twin turbos and their oil feed lines aren't exactly stress-free past six figures on the odometer. And it's not just the motor — the airmatic suspension, the electronic diff, the COMAND system that ages like milk. Every single ancillary on this car was engineered to a performance standard that costs AMG money to maintain, not regular E-Class money. The real killer is the parts pricing. You're not buying Mercedes parts. You're buying AMG-specific parts, and the markup is...