Should I use OEM or aftermarket parts for a JDM car?

OEM Japanese parts are generally high quality and often preferred for safety-critical components (suspension bushings, brake components). For performance modifications, quality aftermarket brands (Cusco, HKS, Tein, Tomei, OS Giken) are well-regarded and often superior to OEM for their specific purpose. Avoid cheap no-name replacement parts for anything structural or safety-related — failure rates are higher and fitment is often poor on Japanese vehicles.