Originally Posted by Jhill

Well this is where I'm confused. You say it's unstable on a bumpy road but then use hotrodz track bottoming as an example which I'll bets it's safe to say isn't a bumpy road. So hitting bump stop repeatedly is not really a good thing so you have three options a stiffer linear spring for more support, a firmer high speed compression damping, or a progressive setup. Setting a stiffer linear spring will give more support and not bottom at the cost of a harsher choppy ride over bumpy surfaces (why I said I think you going the wrong way), a former high speed compression will ride the same over low speed shaft movement but be firmer on high speed impact (and can feel spikey), or a progressive setup that keeps the same small bump low speed traction but resist bottom out in a smoother motion than a firmer high speed compression, usually more ideal for off-road and not as great for smooth track