What is TUV? What is DMSB?
And why does it matter if a part is 'TUV approved'?
TUV is a German organization that tests and approves consumer products. The US does not have an organization that is quite the same as TUV. In US terms, TUV is a combination of UL (Underwriter's Laboratories, seen on household consumer items) and the US DOT. The Germans take their product safety very seriously, especially when it comes to the automotive market. Vehicle state inspections are much more rigorous than in the US and a non-TUV approved part is an automatic rejection and inspection failure! The Germans don't want inferior parts polluting their marketplace.
TUV establishes safety and performance standards based on the original part and its intended use. They test and certify that products sold for automotive use meet or exceed the original design parameters for function, design, safety, and fitment. That means that the part installed has been independently verified to perform safely and in a similar manner as the original product did. Any manufacturer can submit parts for certification - whether they be OEM suppliers or performance manufacturers. Any manufacturer claiming to be an OEM must must submit their products to TUV for testing and certification. For performance manufacturers, like H&R or BBS, TUV certification adds legitimacy to their products so the consumer has the confidence that the product is safe and well designed. That's the only independent way that you can be sure the part meets the same criteria as the original. Generally speaking, parts that achieve a TUV certification are considered better than those that have not been submitted for testing.
TUV is not the 'end-all-be-all' of product quality. Some manufacturers choose not to submit their products for testing and certification and that doesn't mean their product is inferior or dangerous. But having the seal of approval of a stringent, independent agency can go a long way in reinforcing consumer confidence.
DMSB is another German agency but focused on motorsport safety rather than consumer products. DMSB is made up of several German motorsport organizations, including ADAC, and represents Germany at FIA events and meetings. In the US, it would be like SCCA, NASA, BMW CCA, PCA, SCDA, etc all getting together to form one unified safety council. DMSB is responsible for the creation and conformity of safety regulations for racing series, racetracks, marshal and safety worker training, licensing, and standards for product safety. DMSB certification means the product meets or exceeds the standards set by these German motorsports officials and may also meet FIA standards.