I've seen the first actual Japanese customer GT-R car dyno printout:
482 ps (475 hp) and 59.2 kg/m (428 ft-lbs) at the hubs, Dynapack chassis dyno, 4th gear pull , some type of limiter cut in.
http://minkara.carview.co.jp/userid/.../blog/c227132/ if you can read Japanese, but no Japanese required to read the dyno screen shots.