Dyno Chart 240SX S14 KA24DE w/ Greddy turbo kit

Well I'm not sure if you can say that this is a KA with the Greddy turbo kit, since the only thing left from the Greddy kit is the turbo and some of the pipes. The stock greddy kit is decent, but if you want to make more power, it's better to get something else.

Specs: 1996 Nissan 240SX KA24DE - Pauter Rods, CP Pistons Technosquare ROM Tune, 550 cc injectors, Walboro fuel pump, SARD FPR, Greddy TD06SH-18G, Greddy intercooler, custom 3 in downpipe with HFC, HKS Hi-power, 300Z MAF, MSD 6A, Tial External Wastegate.

16PSI, 301 wheel HP, 296 lb-ft, AFR 11.1 This is on a SuperFlow Dyno.

Nissan GT-R V-Spec 550hp, 330 pounds lighter

AutoExpress says that the GT-R V-Spec will pump out 550 horsepower from its 3.8 liter twin-turbo V6 and will actually weigh 300 pounds less than its 473 horsepower brother. The report says that Nissan will add a ‘wild’ bodykit with side skirts and splitters that will provide maximum downforce at high speeds. Inside, the GT-R will be stripped out to reduce weight; however the dash-mounted touchscreen will remain with even more advanced features.

Nissan’s engineers are targeting a Nurburgring time of 7 minutes and 25 seconds to break the circuit records. So expect massive amounts of spy shots from Nurburgring in the coming months.
The GT-R will cost £55,000 when it goes on sale in the UK in March 2009, and the V-Spec will add £20,000. The GT-R V-Spec will arrive in the UK before the end of 2009 and in the U.S. in the middle of 2010.

2009 GT-R Modifications

There's been a lot of articles surrounding Nissan's attempt to limit modifications to the new car and how the GPS system tracks whether you're on a race track and void warranties and stuff.
This article
from Motor Trend gives some detail on what has been done by the famous tuner MINE's and some of the restrictions Nissan has put on the car. Now keep in mind that the US spec car might or might not have these restrictions.