Well, by "similar in design" you mean in what they accomplish, yeah, they're all similar. But there are two different ways to build 'em. Calmini builds theirs from plate steel, and SLR's econo arms are too. The AC arms and SLR's original arms are made from tubular steel.
If you're just looking at replacing the UCAs, they're all pretty much equal. I think all have had an issue at one time or another with an owner being unable to get a proper alignment with them because they were made too long or too short, but it's rare.
Brent
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