Hi Agro,
I have AVO coilovers on my Cobra and they have an adjustment knob on the bottom that is a combined compression/rebound adjustment. There are about 20 clicks on the knob and the range of damping change seems quite good (although I'm only pushing the suspension up and down on my rolling chassis).
Looking at them they are a double tube non gas filled shock and can be rebuilt. There should be a suspension/shock specialist near you that can rebuild them with heavier
oil. Many of the good shops have a shock dyno they can put your shock in to test it. From there they should be able to change your damping rates on compression/rebound to specifically suit your application.
Cheers
