Ehh id stay single turbo. Begining post he wanted this setup since easier to make over 500hp this way than mod the 2.5L.
Gotta remember even though this is an old motor im sure the 3.8L has more tq than almost any turbo 2.5L under 2krpm so its not going to be laggy. I know i went from a 99 sc'ed maxima with a 3.0L at 13lbs psi and going from that 3.0L to the na 3.5L swap i couldnt believe what half a cyclinder did for the low end. So just imagine 2 more cyclinders and 1.3Ls.