I mean, do you think that the upper and lower bushings get loaded at the same time with the same exact load? In the same direction? Because ultimately they do not. Right off the bat the loads from the upper ball joint are split between the two upper bushings, the lower bushing takes all the load without splitting any. And the LCA carries all the spring forces, plus the damper. The bushings aren’t the same diameter, the bushing material isn’t the same thickness. If everything was identical there might be more of an argument to make, but none of it is equal to begin with.
It’s a double adjuster because it allows the strut rod to be adjusted independently from its attachment point. You never have to unload the nut that holds tension on the strut rod and the shoulder of the adjuster. Which is a big reason why there’s nothing to be concerned about. I’ve run the QA1 style strut rods on my Challenger for 70k street miles without a single issue.
For that matter, the other popular style of adjustable strut rod out there uses a regular bolt to go through the LCA and tightens directly into the strut rod. That has the same shoulder problem, and is single adjustable, so the tension on that bolt and the rear strut rod attachment point will change.
I’ve run both styles without issue, although the QA1 style is better because it’s easier to adjust the proper length using the double adjuster. The QA1 strut rods are also not the most expensive adjustable strut rod out there, they’re actually cheaper than several of the other options.
Are you worried about running torsion bars up front and leaf springs out back? They don’t act exactly the same under load either. Or independent suspension up front and a live axle out back? Big differences there. Bottom line is no.
I like running all one bushing material because it makes lubricating everything easier. But other than that, you’re splitting hairs.
