I use the Stainless works up and forward headers on my turbo LS9 RX-7 with a custom crossover into a single 88mm T4 turbo. They have about 5K hard miles on them and have yet to crack/fail. While not cheap.... they are durable I'm making around 1400hp thru them with 2.25" crossover piping and 3.5" downpipe.
Anyone heard anything more on the Holley/Hooker LS turbo headers coming out? I know people saw them at a few events late last fall, but not available yet... seem like a good option between cheap ebays/truck manifolds and the SW headers.