Brand differences in A-arms, Spindles, geometry?

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This is a question I see is "mildly" answered if I search for it, so sorry for asking again, but dont have any Clear answer.

It seems like Ridetech and Speedtech is somewhat "dominating", this is not meant as any bashing or anything. But is their stuff just the best? Or is it biased because so many here use them? (It seems so??) Are they the most up to date and modern?

And is there actually much difference in the geometry the different Companys get With their parts? There will always be some rubbish Products I Guess. But Count them out, would not believe they are big brands, or..?

And most is probably an Upgrade from Stock, my car has Heidts arms and spindles, I dont see many use those, is it becaue they are worse, or just not as much advertised? More for the Hot Rod crowd?

UMI? Heidts? Speedtech? DSE? etc? I dont know all brands, just examples here.

What is the real differences? It could of course vary very much from how each one may put it together, ball joint heights and much more, rideheight etc. But the basics?

If you understand the question? I would love some input or discussion on it, I am not gonna buy anything New, not before I see the need for it atleast. Just wondering.