1985 745t

So I need to replace the ball joints on my brick, and have a couple questions.

The first is can't you just replace the rubber boots and not the entire joint? For some reason I thought I remembered hearing you could just replace the bushings like the control arms... but is the bushing on the ball joing integrated or something?

My next question regards brands. The online stores I use list two ball joint kits, one made by TRW for and another made by an unlisted brand for about $11 less per kit. In the past I have found that the unlisted brand for a component can be a company like Bosch, so I've learned not to just write it off. I'd like to save $20, but I have no idea whether this is one of those situations where I might get a real dog with the no brand product.

I've included the shot of the no brand part below... anyone recognize it? Know who it might be and whether it's reliable? Are ball joints one of those products where brand and reliability are incredibly important? Also, is TRW reliable? Do they make solid products?

Thanks in advance for any help.

-rt