Check your shift points in both normal and performance mode, and only at WOT. I think you'll see the difference. It doesn't move them by much, just enough to hit the peaks of hp and tq at the right times. Remember that our torque curves are VERY low to begin with, so a certain percentage higher in shifts is a lower number than it would be for the S2.
Jet dyno'd and tested with a 93 SSEi that had an intake, full performance exhaust, and 180° themostat. Have you replace your cat with a hi-flow unit? That may help as well.
The quicker revving is the TPS enhancement. The PCM responds quicker to throttle inputs with better-tuned fuel maps as a result of the JET. The Jet sees the TPS changing, and amplifies the amplitude of the incoming signal from the TPS before it'* passed on to the PCM. Works like a charm.
Have you noticed an improvement in mpg during daily driving yet? I did after about 300 miles of the chip 'settling in'.