Most models adjust through the central control screen menu, while a few models (like some BYD or MG) retain physical levers or paddles on the center console or steering wheel. We will check if the drag feel when the system engages is linearly normal.

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.

Due to legal restrictions preventing unregistered vehicles from high-speed driving on public roads in China, most of our dynamic tests are conducted in a closed area (with a maximum speed of around 60 km/h). This is sufficient to test for suspension noise and low gear smoothness, but it cannot simulate high-speed wind noise and tire balance vibrations at 120 km/h.