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.

Supply and demand determine prices. In the Chinese market, mainstream colors like black and white have much higher resale values and market circulation speeds compared to less popular colors (like pink or bright green). Therefore, there is a price difference of thousands of RMB for specific colors at the procurement level.

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.