If your gonna spend that kinda $$ you might as well get a GT30R or a GT3071R.
Here is the link to the thread I was talking about.There are some calculations for a smaller turbo.And specs for my turbo I'm rockin now.
zerothread?id=239945
If you do make an upper Plenum, post up some pics!!!
Are you gonna run Internal or External?Stock type mani or Top mount?
My buddy has a topmount that he's not using, I'll see if he wants to sell it.