Hey Paul,
First do look at the KG-3925. I know the price difference is pretty good but it really is a "better machine" (granted mine still had some errors). I don't know what your planning to cut with it. I had the 2525 and went to the 3925.
As for steppers, I am using 180 oz steppers on my 3925 and it's doing well. You can see
my machine here. If you flip the pullies around the speed is rather fast and the stepper motor does not need to turn as fast so the torque stays high. Of course the resolution is lower but it is still at .001" (or if your a metric man like me
.0254 mm) if I recall. Saying that, 640 oz/in nema 34 steppers from
homeshopcnc would do the trick very nicely.
Keep us posted on your machine
taus