center wheel caps

[kiyakubuke]

when I bought my car the center wheel caps were in bad shape. faded,cracked and peeling. bought some cheap ones on ebay ($24 for set of 4). looked good, but after only 6 months. they are faded as well.
has anyone had similar issues with these caps? do the Porsche brand fade quickly as well?
I bought another set of ebay ones and hit them with coat of clear. we will see how that does.