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.

Testing is mandatory. Troubleshooting electrical devices in the car is part of the standard procedure. We will test the window lift motors, mirror folding, air conditioning compressor and fan, electric seat tracks, etc. Any stuttering or failure of electronic components will be recorded.

For B2B large customer orders, a "sampling + full inspection" dual regulation is adopted. Core parameters (no major accidents, no water damage or fire) are subject to 100% inspection per vehicle; appearance and condition are uniformly graded (e.g., uniformly purchasing Grade A), and panoramic images of all vehicles in the batch along with a core indicators comparison list are provided before shipment.