I can't speak to their durability or such. But, the lack of a TUV, and more specifically a DOT approval would concern me.
This is because should the worst ever happen, and you get in a collision, especially if it included bodily harm or death, Insurance investigators will hold EVERYTHING up to the light to try and sidestep the claim, yours and the other party's.
And surely, the brakes would be one of those items looked into.
Most Insurance Cos. policies prohibit modifying the car and especially putting non-legal (termed Off Road) parts on the car - it's in the fine print.
My best friend is head of auto claim investigations in a 5 state area for a large (read 1 of the Big 5) Ins. Cos. He's been doing this for more than 25 years and so I've heard all the stories... and the list of denied claims because of non-OEM or DOT approved parts is not short.
He knows of my passion for cars and has, more than once, cautioned me against using non-DOT approved parts. Sounds far-fetched, yet it's kept him warm for all these years.
Now, that doesn't mean they're necessarily bad parts. DOT approval can be denied for any number of silly reasons, incl. using the wrong font in listing
DOT on the product. But, it's still the standard most Ins. Cos. insist upon.