I'm going to guess that your fabrication skills are limited.
That being so, the best bang for your buck in a low profile manifold will be a chinese ebay cast manifold, DO NOT buy the tubular manifolds as they will crack and fail. The cheap cast manifolds may not flow as well, but they are stout and will last much longer. Their downsides, other than not flowing particulary well, are that the wastegate location is on only one of the runners. Like this one:eBay Motors: Civic Integra Cast Iron Manifold T3 D15 D16 35mm/38mm (item 200303834366 end time Feb-03-09 21:50:36 PST)
This is not a major concern since your turbo is internally gated, and you will simply install a block off plate over that wastegate port anyway.
If you have the money, get a log style manifold, or what they call a mini-ram. These are incrementally more expensive but see incremental improvements in flow capability. Set a budget for how much you can afford, and then hunt for the best deal on the best possible manifold design.
650 for the whole kit, or for just the manifold, cuz 650 should buy you a decent used mini-ram. 650 for the whole kit... you better stop by Home Depot and check out their selection of black iron pipe fittings.