I've been thinking of going the header route as well but if I do it will be made out of 321 stainless. I've been through several headers before on other projects that were made out of 304 and they just don't stand up to the heat cycles, and once they crack they are done, you will be constantly welding them. For my time and money I'm really leaning towards just buyin the SPA T4 turbo manifold and calling it done. You won't be able to build a decent tube header for what it costs to get the manifold. From just thinking about it at this point it seems to me that there are lots of other places to make the system more efficient prior to building a tube headsr. JMO.
M5
