PMSL at last comment!
Stock R34 does 60 in 4.6, in the most optimum variables/factors. Poorest time is 5.2 (all secs).
UK-spec R34 GT-R has 320AWHP at crank = 280AWHP at the wheels. That is a drivetrain loss of just over 10%, which is very good, seeing as though rival 4wd performance cars such as the Evolution make a drivetrain loss of 20%.