Hello Wolfgang
it all depends on the car. is it a speedster? And, also on the TÜV guy doing the inspection! If you get the wrong guy... you might catch hell for all kinds of things.
I had a 2-inch thick file full of paperwork, engineering reports, orig. tech expertise, etc, copy of the US title, certificate of origin...and, and... incl. a 30 page(!) expertise on the wooden steering wheel alone !
What lenses are you talking about. Generally they don´t know DOT, thus they don't look for it.
They do look whether tail lights are the correct colors: red / amber for turn signals.
TÜV will check that the headlights are properly adjusted and beams aligned.
In my case...its a 1957 speedster....I got classic car license plates...lap belts were no issue at all. No mountings were checked.
EMPI parts are ok. No one even looked ar my discs and calipers.
oil leaks are definitely an issue though. The car better not leak while you´re going through TÜV inspection.
Last not least....the inspection is not cheap...no bargains here! At least not when its the very first one...the one you need to get German papers and plates. Only certain inspection centers are allowed to do those!
Hope this helped.