stevey_frac -
This may or may not help, but here are some similar threads about an XFE tranny into a Saturn Ion, which also uses an Ecotec engine :
Saturn ION XFE? - SaturnFans Forums
Gas Mileage For Those Interested - SaturnFans Forums
I also think they just changed the final drive just like you said.
Here's another website with lots of gear ratios :
Manual Transmission Ratios
CarloSW2