If you NEED a steering damper for bump steer, then you either have some worn out parts, or messed up geometry, probably the track bar.
Yeah... I have a damper on mine, because at the moment i have manual steering and I want to reduce steering feedback in the rocks. kind scary when a tire comes down off a rock, it shifts the steering and you dang near break a thumb. kind of essential for that reason, but if you have power steering its no longer a safety concern. maybe you WANT to reduce feedback in the rocks, fine, add a damper.
but it can't and shouldn't be used to stabilize the vehicle's poor steering characteristics. When i setup my steering, i drove the jeep for several weeks on the street until i got everything sorted out (and arg, even pulled the axle to add more caster) and then put the damper back on to go wheelin. fact is, it drove way better on the street without it and sometimes i take it off if i'm going for a long drive with no rocks involved.
i'm gathering up parts to get rid of it. adding power steering with ram assist. you can do a medium duty ram assist system really easily for about $120 if you have basic metal fab and mechanical ability. I'd post a link, but its on another forum that i'm not allowed to link to, in the toyota pickup section.