hi andy
you can find manifolds from a few places, gcg.com.au have them also check out calaisturbo.com.au as they would have some good contacts for suitable RB manfiolds
or you can check out the sau official business traders. for the turbo it is much the same, ideally but the turbo and manifold from the same place, this will ensure the flange matches and its the correct fit. you should make sure you are familiar with the common turbocharger technology before you go and spend your $