Ack! Just saw this thread.
Yeah, around 65 lbs, if I recall.
I did indeed to the final drive swap of the tallest available 3.52 option (from the 1.3L drivetrain) into my 1.0L Metro/Firefly. Wouldn't have it any other way! Most days I still want a taller top gear.
But note my typical usage is on relatively flat roads, at relatively moderate speeds (typically below 100 km/h / 60 mph).
Acceleration suffers, predictably (guessing it's now 15-16 sec. to 60 mph). As does taking off in 1st gear on a hill ("new" 1st is now roughly halfway between the "old" 1st and 2nd).
Did you do the job already?