2011 Cayenne S: My wife has 21" oem turbo style wheels and after driving on her 20" winter tires, she's decided that she prefers the ride on 20" even though she loves the looks of her wheels. So I'm looking at BBS SV wheels 20 inch. They are machined face with black accent.

Question is, does anyone know of a source for Porsche center caps that match those wheels? I see center caps all over ebay but I have no idea how to make sure the finish will match the wheels.