After reading what Dohmar has been saying, and what everyone else has been saying, i'm siding with Dohmar on this one.
I have read in a HPI magazine, an article which Martin Donnon wrote a year or so ago, talking about breaking 300kw out of a GTR.
If memory serves me correctly, N1 turbos, AFM's, aftermarket computer, and some fuel/oil upgrades, 300kw should be quite easy, provided the tune is done properly.
I'm trying to find the article as i type..