I've always gone for the brand that VAG uses at factory, a word on the use of OEM, this just means that when a company selling you parts wants to provide provenance, they might use the term "OEM" - where this goes wrong is when for instance a company sell Bosch parts, Bosch being an OEM to VAG, it does not follow that the Bosch part you are buying as an aftermarket service part, was a part that VAG ever bought in from Bosch for factory fitment. For example, I don't think that VAG buy in Bosch brake pads or ignition coils, but they do buy in some Bosch parts. I have never ever bought Quantum wipers as they are just a "three versions almost fit all" and not OEM, I've always bought the correct VAG part from dealer, on-line, or where they have used Bosch at factory (Polo/Ibiza) from Halfords. Now if I was convinced that I knew that my S4 wipers were Valeo or Bosch, I'd just them from ECP or Halfords etc.