Okay I'll try and answer everyones questions, but there is a lot of information so I'm going to try and get my thoughts out.
First of all the R200 (200mm ring gear) has two basic versions: Long nose and Short nose.
Long nose:
The ring gear in the long nose R200 came in 10mm and 12mm.
This is simply the size of the bolt use to hold the ring gear to the carrier.
10mm R200's came in 280Z, 280ZX, 300ZX (Z31) till around 1987.
12mm R200's came in 200SX, 300ZX (Z31) from 1987 -Z31 Turbo came with LSD, '88 SS Turbo came with VLSD.
Short nose:
These are the ones that came in 240SX, N/A 300ZX and others.
They came in open an VLSD versions.
Output shafts are not interchangeable between VLSD's and others.
Also there are be other cars that came with these diffs. that I have not mentioned.
The carrier is interchangable between the Long nose and the short nose.
This means any aftermarket LSD made for the 240SX will fit into the Long nose case. Both open and VLSD pieces are available so care must be taken when picking parts. For most applications here you will not want the VLSD unless you can work with it's output shafts.
I used KAAZ part number SAN2655 (2 way).
This is listed in the KAAZ catalog for '89-'98 240SX and some others.
I run a 3.7 gear.
It does make noise mostly turning under light power at slow speeds but it works as it should. Hit the gas and it locks.
If you're wanting to put a VLSD into a Long nose R200; it should go.
You just have to work with it's output shafts.
Sparky I think you will find the S14 halfshafts to long for a Z.
If anyone has any corrections to this information please share.
Chris