Hi Rolf-Dieter,
that is a possibility but now I would be adding another task on top of it, how to check out the repair shops.
Several years ago when I was searching for a 280SL I called up a shop in the area where I found a car and pretended to bring in a Pagoda for an oil change. During the conversation I mentioned that I had run out of the seal in the top of the oil filter canister but hoped that he would have one in stock. "Sure we do. All the seals you need are in the OEM kit that we buy " was the answer!
After a bit more probing it became clear that this "Mastermechanic" had never seen one!
So, no members in the Philly area who could make suggestions or help?