The QA1's will flex less, but compared to a set of boxed stock LCA's it's probably a pretty minor difference. I run them because they have a shorter profile height, so, you actually increase the amount of available suspension travel. Now, that was before they changed the design and added the bump stops to their LCA's, so, if you buy a brand new set that isn't an advantage unless you cut off that bump stop and mounting boss. But based on their profile height without that added bump stop they add almost an inch to the available suspension travel, so on a car lowered significantly with the torsion bar adjusters and larger torsion bars you can get a little suspension travel back.
They also already have sway bar tabs on them. So, if you have a old set of stock LCA's that doesn't have sway bar tabs, needs to be rebuilt and boxed the QA1's start looking a lot more appealing. If you can weld and have the time to rebuild and box the stock LCA's it's no big deal. But if you can't, or just don't want to, buying the QA1 LCA's isn't going to be a ton more money than paying someone to do all that to a set of stock LCA's. You get a new set of LCA's that have new bushings, new pivot pins, sway bar tabs and don't need to be boxed all at the same time.