upgrade exhaust/turbo manifold

[S13 King]

I'm looking into some performance manifolds for the SR20DET and honestly wwhat do i look for? I see prices and I see shiny but what makes one better then the other?Such as there is a JIC manifold on phase2motortrend

then there is this one from Z Fever.com

then this one i found on a japanese site called silkroad

so what is it i'm looking for? I do plan on keeping the T25 on the sr20det for a while, maybe upgrade to T28 internals for short time sake. But later when there is more money would i go with a bigger turbo.

So what should I do?