My spider gears are on their way out (heavy galling, not going to last much longer), and I'm looking for a solution.

A few other threads mention swapping in 31-spline axle/side gears, spider gears and axles as a direct drop in. My questions are:

1. Has anyone confirmed this to be actually doable?
1. From where to source brand new gears? Vendors & part numbers?
1. What vehicles can I use to cross-reference for the axles, either new or used? Part numbers?
1. What vehicles can I source used gears from? Part numbers?

No guesses please, I'm looking for the specifics that are not really clear in the other threads.