Upgrading no-LSD diff to LSD one

[Mux213]

Well if the RNP of the GTS open diff is the same as for the LSD version, then you should be pretty much home free with a new LSD unit, just have someone who knows what he's doing install the LSD and properly adjust the RNP gears or you will be in a world of trouble.

I do really wonder how beyond repair your current car is,

Probably the RNP gear is shot, very possible the LSD is warn internally,so yes it would need to be replaced, but the axles should still be good, and the bearings at the end of the axles should still be good.

The bearings in the diff housing can be bought and aren't expensive. There is a guy in the commercial sales that sells all the bearings.

The RNP is expensive but a worth while investment.

Then all you need is a new LSD, but you need that anyways.