Which model soobys are r160 lsd?
RX turbo. The ones shaped like a "Leone".
You need to change the tailshaft flange - the tailshaft would bolt onto the subi one as the holes are correctly spaced, but the subi flange is bigger in diameter and won't go thru the hole in the 1600 x-member. You could also unbolt the subi flange, put the diff in carefully so as not to get dirt in the exposed oil seal, then bolt the flange back on again once the diff is in. The nuts for the flanges are #%$#% tight though.... My original 1600 tailshaft flange wouldn't fit the subi diff (was smaller in the oil seal area), but the flange off a 180B SSS R160 would
The subi stub axles are held on with a "torx" bolt - a bolt with a six-sided star-shaped head. You can buy the correct sockets at decent tool places. I got the guy who sold me my R160 to undo the bolts before I bought it, so didn't need the special tool. Once the stub axles are off, just swap the Datsun equivalent, including the Datsun bolts, onto the diff.
Why do I know so much ? I spent the last two nights doing the swap
An R180 will bolt in, but apparently needs the matching R180 driveshafts as the dust covers over the side oil seals are different.
get a r180 diff from a 200b
All 200B's I've seen with IRS have had R160's

. Most are live axle though.