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.

China has a large number of luxury cars and a fast turnover rate. For luxury cars of the same year and mileage, the FOB offshore price in the Chinese market usually still has a 10%-15% arbitrage opportunity after deducting shipping costs, especially for models with high depreciation rates.

For older vehicles or those used in high temperature and humidity areas, we will focus on opening the hood to check if the insulation of the wiring harness in the high-temperature area of the engine compartment is cracked or brittle, to identify potential short circuit risks that could lead to spontaneous combustion.