I have had a D30 Ox locker for almost three years, and it has always worked great. About a month ago, I ordered and had installed an Ox "super 35 equivalent" kit in my D35.
The kit is available from 4Wheel Parts Wholesalers: 888-432-7656. I bought mine through my installer, who is a local affiliate of the 4WP.
This kit works great, and while the 30-spline shafts included with the kit are not advertised to be from Superior, they appear to be of high quality:
1) the spline diameter is greater then the shaft diameter, indicating that it wasn't cut from cheap stock
2) the shafts accept ABS tone rings, if that is important to you (it was to me)
3) the shafts are drilled for multiple wheel bolt patterns
My installer knows the Ox principals personally, and has an interest in the local 4Wheel parts Wholesalers. Here's a summary that I have been able to piece together from what he, and others have told me, about Ox history:
Brat in mind that this is my interpretation of events that I have pieced together in my search for the (finally available) "super" D35 kit.
Initially, in the very beginning, Ox was manufacturing the locker on a prototype basis and were not able to meet demand. At this time, they sold directly to the public.
A distributor and axle shaft manufacturer became interested, and the distributor somehow indicated that they could provide financing for needed espansion. As Ox proceeded, the distributor tried to ghain control of Ox outright. At this time, Ox disappeared from the internet, only providing limited support.
Also, some customers had problems with some of their rear lockers, but I believe that the problems which resulted in actual failure were the result of incorrect installation. However, there were reports of some lockers popping out of engagement at inopportune times, and this problem has been addressed with implementation of "progressive gears" in the current product line.
I personally have never experienced a problem.
If you order a locker, though, request the "old style" cable. My kit came with a "new style" cable that, while it was more flexible and more temperature tolerant, would not shift smoothley in my application (or so my installer tells me). Installation of the stiffer, old style cable, fixed the problem. Make sure that you address this issue with the supplier when ordering your Ox.
Meanwhile ... great product (for me)!