after countless hours and visiting multiple forums my question still remains unanswered, I'm try to put. a q45 ring and pinion 3.5 final drive in a s13 open diff and then have it welded, I'm currently running a ls/t56 combo with a vlsd and it Doesn't feel as potent as it used to, and I've always wanted a welded diff but the stock final drive is cancer, so the most I have found about my question was, it's possible to swap a q45 R&P in a s13 with a LSD (tomei or kazz) , and I also found that you have to swap all the bearings and spacers from s13 pinion to q45 pinion, I have not found Any forums/ thread were someone swapped the q45 R&P in a s13 open diff, so please any help and info is mucho appreciated!

I don't really know if this is a viable swap. I've ran across some threads on competing sites where either someone was considering the swap, or talking about the swap, but nobody's DONE the swap. It would be interesting to see it done, but it's basically going to be a full custom ordeal. By the time you spent all the money on making it happen, you'd be better off just swapping a standard R230 into the car. The Armada uses an R230 for its front diff, and it's an open differential. Since you want to weld the diff, it might be best to get one off a wrecked Armada/Titan/Pathfinder and swap it into the Q's R230 housing.

Q45 is still an r200, but iirc, the pinion is thicker and wont fit in an s13 or s14 housing. The j30 r&p will, I've done it. Also the q45 ring uses thicker bolts and I'm not so sure about an lsd that'll fit the 30 spline output shafts.

I'd recommend, if you can find it, an early j30 (pre '94) diff and axles (better cv joints and 5 bolt flanges) and get an lsd for an n/a z32.