Ok, after a few minutes of searching the only solid number I could find for the HX gearing was the final drive ratio.
5G EX/Si: 4.25
6G HX: 3.72

Just the final gear will give you a noticable difference in acceleration, in this case the car will take longer to pull through each gear with an HX final assuming the same (or close to the same) gearing.

For compairison, most B-series gear boxes come with a 4.40 final, and the late JDM ITR came with a 4.785 final

The HX CVT has a supposedly has a 5.81 final, but the CVT is a creature of it's own anyway.