I removed the stock rear diff a few weeks ago, and just re-installed it last Saturday (9/25), as I decided to have my race shop install a Quaife ATB LSD.
Here's my notes:
Started the parts removal (i.e., exhaust, driveshaft, RSTB, etc.) this afternoon to allow for the removal of the OEM rear diff, since I decided to put my QJ's to use and perform the R&R of the rear diff myself, and then drop-off/pick-up the differential w/Quaife LSD installed by my race shop in Tigard. They can turn-around the LSD install in a few days.
I'm currently at the step of removing the diff from it's mount. Looks like two bolts near the front, and one in back. Tomorrow, I'll be using a 800-lb capacity transmission jack from HF to lower the diff while I pop the half-shafts out. Glad I have the 2016 Service Manual for reference - still have to drain the gear oil, remove both wheels sensors, and then the vent tube as the diff is lowered.
UPDATE (1): The rear diff is out! I drained out the gear oil before I started to loosen the diff mounts. Here's what the drain plug magnet looked like after 15k miles (my Q has 30k miles, and the driveline fluids were changed-out @ 15k miles):
After the fluid drained out, I bungeed the park brake cables out of the way, and set up the rubber bungees for supporting the half-shafts later. The two axle speed sensors were removed, and I tucked them on top of the rear subframe.
I used the transmission jack with its flat plate to hold the diff case while I removed the rear nut and the two bolts towards the front of the diff case. I enlisted the neighbor's help to make sure the diff didn't move off the jack's flat plate as we lowered it. We disconnected the vent line, and also pushed out the plastic rivet for the tubing retainer, too.
Everything went according to plan until trying to dislodge the half-shafts. My neighbor brought over a better prybar set than I had, and after trying to gingerly pry on the trigger wheel, which I know you're not supposed to do, we simply used a little more muscle and "popped-out" the splines. Despite what the SM says, the spacers just inboard of the trigger wheel can't be used as a prying point, because they never make it past the diff case. After sliding the half-shaft splines out, I moved the diff out from under the car. I wrapped the rubber bungees around each half-shaft to keep them from falling towards the floor, which, if left unsupported, would put unwanted stress on the outer CV joints.
Here's how it looks with the diff out of its usual space (yellow towels are there to keep the boots from getting nicked by sharp edges):
As for getting the Quaife LSD installed, it looks like early Monday morning me and the Mrs. will put the diff into a sturdy container, load it into the SQ5, and travel down to the Tigard-area race shop, since I'm not fond of Fedex Ground delivery right now.
UPDATE (2): Dropped-off the rear diff, or "pumpkin" on Monday (9/21), as planned.
Well, I received an email from the shop this evening (9/22) and it's all buttoned-up and ready to be shipped-back tomorrow. They will ship it UPS Ground, which should only take one day to arrive from OR to WA.
UPDATE (3): Received the diff via UPS this morning (9/23). After starting the install, my neighbor and I realized the circlip on the right inboard CV shaft is missing, so I had to order one through the Infiniti dealer ($6.42). I search all over for it, even call the shop and asked if they found it in the OEM carrier, but no dice. Oh well, I'll likely find it on the aggregate driveway some day in the near future. The circlip should arrive at the dealer on Saturday.
I should be able to finish the install on Saturday, but it will still be a couple of weeks before I can try it out, as I decided to remove my brake calipers and send them out for a rebuild and a color change.
UPDATE (4): The circlip arrived at the dealership this afternoon (9/25), so I made the one-hour RT trek to go get it. Once back at the house, I was able to install the circlip by hand with a small amount of wheel bearing grease. We determined the best way to drive the CV joint shaft into the diff (must overcome the circlip tension) was to install the diff with the two mounting bolts in front and the rear nut, and then use a block of wood on the rubber boot where it meets the CV housing. That would give the axle spline a straight shot (not at an angle). A few swings with hammer on the wood and the axle spline was fully-seated.
With that out of the way, I proceeded to torque the diff mounts to spec (74 ft-lbs for the two front bolts, and 77 ft-lbs for the rear nut). I re-installed the IE driveshaft (D/S), which with its lighter weight and one-piece design, can be installed with one person. The only issue that came up - I couldn't torque two of the four bolts at the front flange of the D/S, as they were at the top, because my Q is in Park, and to rotate the D/S, it has to be out of Park. However, moving out of Park means pressing the brake pedal, and I can't do that because I would blow the caps off the brake lines, since my calipers are off getting rebuilt. I debated screwing with the brake pedal switch, but I opted not to.
Oh well, my remaining tasks on the driveline are filling the diff with fluid, torque the front D/S flange bolts, re-installing the FI X-pipe and mufflers, and re-installing the tunnel brace. It can wait until I get my calipers back..
UPDATE (5): My Stoptech Trophy calipers are disassembled, cleaned, and ready for paint. Once the eight (8) halves are painted and oven-baked, the specialty shop, Goldline Brakes, will re-assemble with new seals and dust boots. Note: I requested the calipers to be separated, so the bolts holding the halves together, the interconnect pipes, and the pad stiffener (bridge) could stay their original colors, so the calipers don't look so mono-chromatic.
What they looked like before (front/rear):
. The quality, fit, and finish are perfect 
