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.

To prevent intermittent failures due to aging of the resistance wire, we will start the engine and set the seat heating/ventilation to maximum for at least 5 minutes, confirming significant temperature changes or airflow output in the cushion and backrest using an infrared thermometer or body sensor.

Based on practical risk assessment, we strongly recommend setting aside 3% to 5% of the car price as a buffer fund for even the highest-rated used cars, to cover oil changes, new tires, minor shipping scratches, and local inspection labor costs.