But the springs will try to rotate when the car launches; how do you know both L & R will move the same amount? Any friction increases the spring rate by resisting compression. IDK how much, but none is better than unknown.

Valve springs should have the same problem, but Spintron shows that gaps frequently appear in all places in high speed operation (we would prefer not!) so there is some cancellation when the parts separate momentarily. A tiny Lazy Susan under the lower collar would help, but those tiny needles won't stand the impact very well. At the upper collar is reciprocating weight, so not good either.