The '93 FSM listed at the top of the board will have everything you need to swap the diffs out. The front is straight forward bolt-in provedure, only 3 bolts hold the diff in place, 4 on the drive line, and 6 on each of the CV's. The rear is just as easy, just a bit more messy. There should be enough play in the brake lines that you shouldn't have to remove them, unless you want to install new axle seals.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed