4S dealership records are directly connected to the manufacturer's database, making the data hard to tamper with and the most reliable, with original parts guaranteed; third-party repair shops usually are not connected, making their data unverifiable. Therefore, we only consider the connected records from 4S dealerships as valid historical documentation.

Test-drive cars experience much more mechanical wear due to extreme conditions like cold starts and emergency braking compared to regular family cars. We can identify this by tracing whether the first owner was a 4S dealership or the manufacturer. If so, we will reassess its value based on "operational intensity" standards.

Chinese passenger cars produced after 2005 have fully transitioned to asbestos-free brake pads, clutch plates, and gaskets. However, for export to countries with strict regulations, buyers must pay for sampling and testing by a NATA-accredited laboratory before shipment, and obtain an asbestos-free certificate.