Well I finally got around to becoming a member of SAU, I'm part of the R31 Skyline Club.
This just happens to be my car, I think someone wanted the dyno graph:
The red line is the new motor RB30DE (186 rwhp) and the green line is the old RB30E (134rwhp).
Hoping that the diff and gearbox hold together down the track it should be good for approxish 14.3 secs, just about the equivalent of a turbo 1J in a soarer, with very mild modifications.