It would be simpler to just transplant the heart and muscles into the new body rather than a Frankenstein maneuver hacking together the XFi to the HF tranny.
Besides, Darin has already transplanted the lowest ratio transmission (Swift 1.3l) into an XFi (modded) engine, and said that the engine had *just enough* gumption to get it going up hills in gears that previously easily got the Firefly moving.
If you go too low on it and it lugs horribly with the HF transmission, maybe you could rig a Saab turbo into it and make it a three manufacturer vehicle (but you toss a turbo onto the G10 and you'll likely have to reinforce it) and really make it a unique MPG Franken... uh..machine
. I look forward to the start and (hopefully) finish of this build. Good luck, and we are here for support!