DDing rear coilovers on bad roads

hey guys -

Is anybody north of the frost line, where huge frost heaves and expansion joints and massive potholes and shitty pavement are a way of life, DDing rear coilovers? How long you been doing it? I don't drive the Z even close to winter, just May-October, but the roads in Eastern Ontario look like something from a Belarussian trucker's dash-cam. Honestly when I am down in PA or MD or around DC, the difference in the roads is incredible.

I'm not concerned about ride quality (I don't think 6K springs are going to be much stiffer than what I'm already running,) I'm concerned about the durability of both the coilovers and the rear of the car now that it's all up to the rear shock tower.

Obviously people are drifting and racing on them but if I'm not mistaken, those are g oing to be mostly lateral stresses that are shared out across the whole suspension, as opposed to getting a constant day-to-day hammering in the vertical axis.

Anyone noticed, like, their shock towers deforming over time?