Not really, just dont go to the dealer. Body parts are just as much or less as other cars at junk yards (fenders etc…), used oem parts are really cheap, aftermarket product companies such as for turbo setups cost more because they include everything needed and not just the things to get by.
But if you decide to buy everything new at the dealer if something may break: Bmw Oem doesn’t cheap out on electronics or workmanship from the factory, so all gauges, clusters, computers are usually made by VDO, Siemens, or Bosch. So you’re actually paying for good stuff that comes factory.
I prefer and suggest buying parts used, because a lot of times parts that fail, may be due to user error, not maintained, or “lemon” fault from the factory. So most likely if your non-stress component (not like a bushing or a shock, but such as an ecu/computer) has failed, most likely it was just that unit and a used replacement unit will due just fine.