Howdy all, plenty of good advice in here and just one more thing to consider, to possibly have a match in engine to proposed new 2530, big dollars on supporting internals is on the cards. I cant help but think that maybe a rb26dett front cut transplant might be your best option.
Straight up 200+kw atw and twin turbos, newer motor-more parts available, however, to keep within the theme of this thread consider the pipe work from induction thru turbo to inter then back to engine, and dont oversize too far if at all from factory specs and you will be well on the way, also consider the pipe work lengths, greater dist. airflow to travel the greater the lag, 450mm wide bar&plate intercooler instead of standard 600mm may help this also. ARC have some good info on this, ring them and have a chat. Once you have decided upon your turbo look at purchasing from the US, bought-shipped to your door its still heaps cheaper than buying them here + no sales tax- my bro has bought 2 (separate evo2 rocketship builds) and saved nearly $1000 on each unit.