Experience turbo lag and power surge during road tests; check for significant oil accumulation at the turbo intake and intercooler connections (slight oil vapor is normal); and use OBD to read the real-time boost pressure peak to see if it meets factory settings.

The catalytic converter contains precious metals, making it a target for theft. During chassis inspection, we check if the welding points of the catalytic converter are in their original state. Once verified, the vehicle will be sealed after being handed over to port logistics to prevent disassembly and resale.

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.