When sourcing 5x100 18-inch wheels, you must verify the PCD (Pitch Circle Diameter) is exactly 5x100mm, as this is common for vehicles like Subaru, Toyota, and VW. Additionally, check the Center Bore (CB) size; if the wheel bore is larger than the vehicle hub, you will need hub-centric rings to prevent vibration. Ensure the Offset (ET) aligns with the buyer's vehicle clearance to avoid rubbing against fenders or suspension components. Finally, confirm the Load Rating meets or exceeds the Gross Axle Weight Rating (GAWR) of the target vehicle.