What are the differences between genuine parts, OEM parts, and aftermarket parts?  

**Genuine Parts**  

As the name suggests, genuine parts are produced either by the automobile manufacturer itself or by specialized parts manufacturers authorized by the automaker.  

Authentic genuine auto parts are crafted to perfection, with quality nearly identical to the original components—free of minor defects and consistent in appearance and performance. They come with professional certification and are stamped with the genuine part's logo and part number.  

**Aftermarket Parts**  

Aftermarket parts refer to components produced without authorization from the original parts manufacturer. Typically, there are many producers of such parts, offering a wide variety of products. These parts mainly imitate genuine parts and are visually similar. Compared to genuine parts, they are more affordable.  

**OEM Parts**  

High-quality aftermarket parts are referred to as OEM parts. These are components produced by qualified manufacturers that were originally one of the official suppliers to the automaker.  

However, after their contract expired or they were undercut by cheaper competitors, they were removed from the automaker's supplier list—yet they continue production.  

The key difference is that OEM parts bear the manufacturer's name, brand, and production certification, and are provided through legitimate channels. These manufacturers are part of the automaker's approved procurement list.  

Their quality and after-sales service are also guaranteed. In terms of craftsmanship and appearance, they are second only to genuine parts but are significantly cheaper.  

For example, if a BMW bumper is produced by a parts manufacturer but does not carry the BMW logo on its packaging, it is considered an OEM part. Omitting the logo is an industry norm.  

**Salvage Parts**  

Of course, aside from the above, there are also parts salvaged from used or scrapped vehicles. Although these are genuine parts, they are referred to as salvage parts.