Here's another chart that shows some of the gains throughout the rev range.
One interesting thing we noted today -- the Z either needs a key cycle or two to allow the ECU to adapt (we have no datalogging devices, so this is just speculation), or it is really wise to allow a little cool down before dynoing.
In either case, the above runfiles are fair comparisons; both were the first runs after allowing the car to cool down a bit and the oil temps were at ~200* F.
Headers, cat back, intakes, and finally tuning yet to come... stay tuned!