Not sure who's the original supplier. The genuine VW/Audi 06F109088J is listed for $820usd. Others, on the cheaper side, I see are listed at $50 and up. I suppose I would feel safer with the "genuine" offering; made by one of these A/M companies and marked up. But I would trust an A/M offering from FCP or ECS (here in the states) because they have "Lifetime Warranty" for all parts. Now those warranties don't mean they will cover all of the damage created by a failed part, but it's something at least.
I personally would maybe go with: Febi, Bremmen, or Vaico.