So there are a few differences between the PST and QA1 strut rods. The first is pretty obvious, the QA1 strut rods are primarily aluminum. On the PST strut rods everything is steel. Next biggest thing in my opinion is how they attach to the LCA. The PST strut rods use a bolt to go through the LCA and into the end of the threaded tube. The QA1 strut rods use a double adjuster, one end threads into the end of the tube with a jam nut and then the other side goes through the LCA, so that a nut is used on the backside of the LCA. The difference there is how the strut rods are adjusted. On the QA1 strut rods you can just loosen the jam nuts and spin the tube like a tie rod adjuster, that changes the length of the strut rod. You can do that with the nut on the backside of the LCA tightened and just the jam nuts loose. With the PST strut rods (and others like them), you have to loosen the rear bolt, set the length by spinning the tube, and then tighten the bolt up again. You can't tell if you got the length right until you torque that rear bolt and cycle the suspension through to check for binding, and if you didn't get the length quite right you have to loosen the bolt, adjust the length, retorque it and recheck for binding. Needless to say, it's a much easier process to adjust the length of the QA1 strut rods and check for binding than it is with the PST strut rod or others like them. With the QA1's you can torque the pillow block at the front, torque the nut on the backside of the LCA, and then just spin the strut rod tube as you cycle through the suspension. Once you've got it right you just set the jam nuts.
The double adjuster on the QA1 strut rods does mean that the LCA has to slide back in order to install the strut rod though. Which means you have to pull the torsion bars back and remove the LCA pivot nuts. So the QA1's are a little harder to install initially if your suspension isn't fully apart. Because the PST and other strut rods have a bolt that goes through it means the strut rod without the bolt is short enough to fit in front of the LCA even when the torsion bars and pivot nuts are installed.
As for the life of the aluminum, I have QA1 strut rods on my Challenger (well, CAP actually, QA1 bought CAP and the strut rods were the only thing that didn't change). I put over 70k miles on them, daily driving the car in all kinds of conditions and never had an issue. They're still in great shape.
