Looking at the front and rear diffs side by side the rear looks bigger, start measureing and they are in fact the same, I think the tone ring must make the rear look bigger.
When I installed my rear LS I didn't need a slide hammer, the axles slid right out after I removed the retaining bolts. I did not remove the pinion gear from the housing so all I did was measure the postion of the ring gear and make sure it went in the same. No special tools, just a sterit ruler. I did check the contact pattern and it checked out fine. It makes no noise and runs cool. I would start looking for another LS for the front but in a year or so I am planning on selling my Kia.

Dennis