How to choose between original factory modified parts and branded aftermarket parts? Is there a big difference between them?

Original factory parts match the vehicle’s native CAN bus, allow plug-and-play installation without wiring damage, support programming at official 4S service centers, and come with reliable warranty coverage. Branded aftermarket cosmetic parts offer great cost performance; carbon fiber kits and body kits are ideal for appearance enthusiasts. Low-quality unbranded generic parts often suffer from uneven panel gaps, electrical fault codes and abnormal rattling noises. For electronic upgrades on BMW, Mercedes-Benz, Audi and Porsche, original factory parts are recommended as the top choice. Reputable aftermarket alternatives are acceptable for exterior styling parts. Part numbers are available for all components to verify authenticity.