Looked at doing the same to my R/T. You need a significantly bigger turbo than a GT30, unless you plan on going with twins. I was looking at a single T-72 at 9psi which would support around 600 crank HP and keep it in the efficiency range. 12-14lbs would put you somewhere in the neighborhood of 700-850 HP.

There are probably much better experts than I who can chime in. I spent a bunch of time looking things up and acquiring some things to do it but the truck got wrecked.