Is the manifold on the first page a copy of the greddy manifold for the Gtir? I remember back when I first got my motor, I looked for kits and Greddy was the only one that offered a tubular manifold. It was only offered in JP or UK tho, so its kinda possible.
As for getting a good copy of this manifold, I remember on supraforums...a member built a manifold and sent it to china to have it produced. The first sets were crappy. So he found another guy, the next batches came out great and everyone bought them, they never had problems with cracking and became known as the China Manifolds. It really depends on what the buyer is willing to pay for in materials, the chinese just make their margin on what you send them.