Unless the Borg Warner rear axle assembly is a narrowed one from a Skyline, or other suitable car, it will not be an improvement over the H165 version that comes standard under the 1200 utes.
The advantage of the H165 differential is that it comes in a variety of ratio's, has LDS available, & you can switch these into your ute's rear axle housing in your driveway, in an afternoon.
You can't do that with a Borg Warner unit.