Very nice FC. Welcome to the site.
that's some awesome gas mileage. hahaI'll comment on the 88-92 626 GT..
Excellent power, all the great torque of the F2T, but 4 doors of invisible to Police goodness.
Here is a good idea of what mileage you can expect:
Scalded Weasel (Mazda 626) | Fuelly
Best I've gotten is 33 on all highway driving, worst has been about 22 mpg, average is around 24-27 mpg. (it seems I missed a fill up, so there is a spurious 52 mpg record on there.. I'll fix that soon).
With the GD cars, if you really want to get better gas mileage, it seems a wideband + MegaSquirt is the next best thing after not abusing the gas pedal.