The best approach is to start by finding the part numbers in the Porsche Boxster parts listing:
https://www.porsche.com/all/media/pdf/originalparts/usa/986_USA_KATALOG.pdf and then do a Google search suing the part number.
These are simple, non-critical parts, so I would have no hesitation buying them from eBay.
You can also contact Woody (itsnotanova in this forum) and ask him if he has the used parts.
I suspect for something like this you may as well purchase new parts,