It is a genuine part and the mechanic has worked on my brothers E class, my brothers friend's C43 and my cousin's 330d and I've not heard one complaint from any of them. I only went to his garage for the first time yesterday and I was quite surprised to see how clean his garage was, the floor was clean and everything was organised,there was no bs from him he was quite straight forward he first told me it looks quite an expensive job, fearing my credit card was about to get hammered he made a few calls to various merc dealers and he managed to get the item at trade (£100) and charging £60 for labour and apparently he does not charge vat on the labour to people he knows, I will let you know how I get on.