Understanding the hierarchy of parts is critical for quality control. OEM (Original Equipment Manufacturer) parts are made by the company that built the original parts for Kia, often branded with the Kia logo. OES (Original Equipment Supplier) parts are made by the same manufacturers but sold under their own brand (e.g., Mobis, Bosch, Denso). Aftermarket parts are produced by third-party companies; while often cheaper, you must verify they meet CAPA (Certified Automotive Parts Association) standards to ensure fitment and safety.