I want to fit a 7'5" rear diff to my Esc Cos.. If you had a choice of 2wd or 4x4 rear driveshafts (I have both) is it better to use the 2wd's? as I heard they where stronger?

If so are the 2wd driveshafts a straight swap if you have the correct output flanges on the 7'5" diff?