There's going to be some impact slam on these no matter what IMO. On my motorhome there are no isolation bushings between the coach and the E450 frame (such as a pickup truck would have). The large multi-leaf spring packs are noted for friction and for transmitting impacts. The rear tires run very hard and have strong sidewalls (so set them to weight dammit :). So anything the shocks can do is really a plus. There are times (when driving) I think the Koni shock valving/control is really ingenious with very nice ride motions.