No existing vag manifolds as far as I know, I made mine out of stainless. You can buy one from ATP in the states, don't know about the UK. There was one for sale in the parts for sale a while ago, check out forum member 8pot. Are you building the kit yourself?. I may be able to help as I have turbo'd a 2ltr 16v in my mk1

. I am in the process of making another manifold, so the one I am using will be up for sale soon.
Steve.