We maintain an absolute skeptical attitude. In addition to regular visual inspections, we focus on checking for sediment accumulation around the sunroof drainage channels and look for water stains under the A-pillar trim and front floor mats. This is the only effective physical evidence to determine if the sunroof drainage holes are blocked, leading to hidden leaks.

The standard set is: 1. Commercial invoice and sales contract - issued by the exporter; the basis for customs valuation. 2. Packing list - exporter; details the vehicle and any spare parts shipped with it. 3. Bill of lading - issued by the shipping line; your proof of ownership of the cargo. Never pay the full balance before receiving at least a copy of it. 4. Certificate of origin - issued by the China Council for the Promotion of International Trade (CCPIT); some countries require it for preferential duty rates. 5. Export customs declaration - Chinese customs; confirms the car was legally exported. 6. Pre-shipment inspection report - issued by companies like Intertek, SGS or the EAA scheme, if your country mandates it. Ask the exporter for scanned copies of all documents before shipping so you or your broker can verify completeness.

We will use a megohmmeter (insulation resistance tester) to measure the insulation resistance of the high-voltage bus. If the resistance value is below the national safety standard, it indicates a risk of leakage, and the vehicle will be deemed unqualified.