Precisely, why would an M50D need a turbo recon when all others don't if properly maintained. The turbo failure is not due to the turbo itself but mainly blocked DPF, dirty diesel and oil. That is easily preventable by making sure DPF regularly regenerates, using cleaner diesel and changing correct oil at max 10kkm.
10000%. Bmw Dont design these tri or quad turbo cars to be problematic. They're designed to produce power to weight and have issues not because the turbos fail. The turbos are actually a system of many other issues.
BMW also uses CBS for maintenance which means oil gets changed on a high performance engine very infrequently. Not because its good for the engine to have it changed regularly, but because they carry the cost of changes for an apparent problem which wont be theirs. ie cheap out on maintenance while in MP, you pay for it down the line when out of MP.
This is why its called preventative maintenance.
On the Diff they use bolts which are prone to snapping where the car mates between transfer case. The bolts are cheap because by the time they fail and snap/need to be drilled out, they dont pay for the repair. The preventive maintenance is to have them removed beforehand, since most of the time they're bent/rusting, and replaced with forged parts, which are far less likely to repair. The car is not built to be be bulletproof. If that was the case, everything would be forged/heat treated.
Hell your engine itself is cast alloy because its lighter and cheaper and they can use recycled material (raw). Not because a cast alloy block is in any way better overall.
This is a business, they dont make money if everything lasts forever. See thru the BS of not changing things unless theres a problem, and you find small costs now, that save big money down the line.