51718146205 what does it do?

[LtScheisskopf]

Hallo forum Volk.
There's a couple of trim panels that go under the car (1996 M-Tek 5sp), mine are trashed and looking to replace them. They are a bit pricey but if they have a critical function I'm going to move them up the list of priorities. So far I haven't found their purpose, which of course there has to be one, I just don't know what it is.

The part numbers are:
51718146205
51718146206

Thanks for the help.