Recently upgraded my 1983 Z28 from 26 to 28 spline axles and LSDiff, now the rear end thinks it's a 1990-1992 Camaro. I was surprised at how few details are available for these products, so I'll share my findings.
Superior Axle EV10-4 (Made in USA) kit includes outer axle bearings by Torrington USA, seals, and 12mm wheel studs (of unknown origin). This kit is rarely available at Summit, I got mine from Street Side Auto, same price. The axles are indeed unpainted, accept 1/2" threaded studs and have .484" bores for press in studs with a knurl up to about .491". The studs included in this kit are too thick with a .500" knurl, identical to the GM factory studs made for a .490" bore (spares for front hubs I guess). Remove the hard wax-like preservative from the splines for ease of installation. The 28 spline axles measure minimum diameter in the splines of 1.15" compared to 26 spline axles with 1.05". Not included in the kit, are "C" clips. Other than the wrong studs, I'm happy with this product.
Tru Trac 912A317 branded "Detroit Locker", turns out is made in Taiwan. This is a 3 series carrier for gears of 3.23 +, gear flange location is identical to the factory carrier, so I re-used the same ring gear and spacer/shim setup and has worked good so far. Not included are carrier bearings, I used new LM501349 bearings and LM501314 races.
Installation tips : Have 2 axle stands and 2 jacks, to remove the carrier I had to drop the panhard bar from the driver side, use the jacks to lift the rear of the body and keep the body from falling laterally. The ring gear bolts are LEFT hand thread. When removing outer axle bearings, I do not have the special tool or a slide hammer, I wanted to try using a punch over 5 feet long to hammer them out, but didn't have one. What worked was to insert a 1 3/8" socket from the diff opening and push it down the axle tube up to the backside of the bearing. Have a 5" long 1/2" bolt already protruding from that socket with the threads to the outboard. Place a 1 7/8" socket on the outside edge of the axle tube, the threads of the bolt should be sticking through drive of the large socket. Add washers and a nut, you now have a bearing puller. Other than that, tear down and installation was easy. You might want to check that your E-Brake works on both sides, as the Tru Trac needs resistance in some situations.
Tru Trac LSD is a vast improvement over open, especially in snow, even hooks up in reverse, makes no noise, operates smoothly. Drives like a Z28 should, 2 strips of rubber left behind.

 

I've also ised the Superior axles in a couple of projects, they have always worked well for me too. I recommend them alot. If you come across them by my suggestion, I'm glad to hear they were satisfactory.

Next time, to remove the axle bearings & seals, use a 6' piece of galvanized water pipe. BY FAR the easiest way to handle those. Doesn't even vaguely resemble work, so no one will threaten to revoke your man card over it. You don't even need a hammer, you can just slide it in there against the bearing, and it'll bash em RIGHT out. Just did one that way the other day.