Adding new trailer coupling, which manufacturer? Ebay > Scrap???

Hello, I want to replace my current detachable AHK with a new star. The reason is that Zughagen doesn’t go down any more anyway, furthermore it is slightly to the right, noticed when I had the bicycle rear carrier on it and above all it is very rusty under the car. There I can already pop off the rust is 2 – 3mm thickness. Now the question to you, which manufacturer, except the original ones, can you recommend? Do the what from Ebay? Not that this one after a yes You start rusting again. e.g.:http://www.ebay.de/…/121073526542?…