Yes, I agree, but I also mentioned "compression", and that it might also be a factor in that the front leaf spring attachment point is basically pushing the entire chassis forward with all the multiplied force the motor can develop, and that force then flows thru the floor pan (which is nearly useless) and also makes effectively, 2 90Deg turns as it flows thru the rocker panels, which is I suspect what boxing them achieves/improves, but not likely very effectively, so what the aftermarket subframes may accomplish best is direct compressive transfer of the actual acceleration of the car, and then the shape/ diameter is not quite as important, but of course only in regards to this force (ie not bending). IMO there is lot going on here, and no solution is ideal until those forces are understood and weighed, and the application taken into account. It seems for years there have only antedotal solutions and monkey see, monkey do, and no one asks why?

And isn't the twist from "planting" the left rear, not the right?