I just swapped my differential not too long ago. I was doing it alone and it took me about a day. The hardest part is getting the new pot into place. I didn't have any means of holding it up there except my dad helping me as I try to bolt it. That thing gets real havey real quick. The axel shafts are just a lot of playing around with a ratchet. Make sure you have a good 12 point bit for the bolts. The bolts tend to strip the bits much quicker then the bit the bolts.
It's a real fun DIY, just take your time and do everything as the manual says since those parts are kind of important.
Clean everything when you get the old pot out and make sure to oil the bolts before reinstalling them. Use threadlock if you are reusing the old bolts, or get new ones.
1985 190E 2.3L - a constant project.