I recently went through an ordeal with ball joints on both of my rovers and have tested several manufacturers' offerings so I made a video describing my experiences with them.
Just wanted to share and hope it helps you all out. BTW, by the end of the video I got the terminology for "taper" and "seat" correct, I think. lol
Also, the other point is that the bolt holes on the Delphi that I received and installed previously did not line up with the factory bolt hole locations on the hub assembly, so instead of drilling out the holes on the Delphi to make them larger, I returned them under warranty.
I will be installing the Moog joints on Rover 2 this coming Sunday, so I'll update you on how to install goes and how they perform.