TomrayI

I need to replace the fuel cap on my 2014 A4. On the web site for European car parts it is listed for about $50. I have found one for a Porsche Macan for $16 dollars. Since these vehicles are the same platform I am thinking of getting the one for the Porsche. Are these interchangeable? What differences are there between them to make the Audi one so expensive? I have compared the two and physically they look the same.

SMac770

Looks like the fuel filler cap has undergone a number of revisions:
8K0 201 550 N is now the current revision for gas engine (CAE).
8K0 201 550 P is now the current revision for the flex fuel engine (CPM).
Why is it $63 MSRP? Who knows. Audi really trying to milk the revenue on replacement parts in recent years with stupid prices on a lot of B8 components.
Is the Porsche one suitably equivalent? No idea. The NAR Q5 uses the same caps as all the NAR B8s (A4, A5, Q5). What fuel cap are you looking at? 95B 201 550 E? That's for the 95B; the 95B-2 use different p/ns.
I'd be surprised if it didn't work, personally. But you could also just grab one off any B8 A4, A5, or Q5 as well. If you do have the flex fuel engine, then any B8.5 A4 allroad and B8.5 Q5 2.0T will have that engine. A4 sedan and A5 will depend on transmission.

TomrayI

Thanks for the information. This was very helpful and I found the Audi part on a different site for much less.

MarkDoronin

Check out the Avtopro catalogue https://avtopro.es/catalog/ I think I've seen what you're looking for there