As everyone knows, the Geo Metro convertible had a more peppy transmission than the other Geo Metros. Since "peppiness" wasn't what I was shooting for
I pulled the 4.39 ratio tranny out of my convertible and replaced it with a tranny from a 1992 XFI (you can see the car on my parts car page). A few people
warned me that the XFI tranny was going to be geared too low and it would be a pain in the butt to drive as well as actually cost me mileage. This really didn't
make sense to me since I wanted to get the lowest possible RPMs while cruising. Well, after installing the tranny I'm only turning 2200 RPMs @ 55 MPH 
instead of the 2500 I used to be turning (a 14% drop) the car feels quite sluggish. It is OK for cruising but it kind of gets on my nerves for around town driving.
As far as mileage, it looks as though I gained about 4 MPG (from 45 up to 49 MPG). FWIW, I was worried a bit about this before installing the tranny but the table
 below shows that the 4th gear in the XFI tranny was about the same as 5th gear in the convertible. This meant that if I didn't like
the install I could just drive around in 4th gear and it would be like nothing had changed.
So, would I do it again? Sure, but I bet I will be pulling the tranny out if I ever sell the car (no one else would ever want to drive it like this). 
    1.3 Swift to mid year '95 98-01 1.3 Metro XFI 1.3 Swift mid year '95+ GT, GTI, up to 95 Metro Vert, 96+ Metro
  Final Drive 3.52 3.79 3.85 3.95 4.10 4.39
1st 3.416 12.024 12.947 13.152 13.493 14.006 14.996
2nd 1.894 6.667 7.178 7.292 7.481 7.765 8.315
3rd 1.280 4.506 4.851 4.928 5.056 5.248 5.619
4th 0.914 3.217 3.464 3.519 3.610 3.747 4.012
5th 0.757 2.665 2.869 2.914 2.990 3.104 3.323