Haven't had a chance to road test it yet, but I don't expect it to. I've had these on a Suburban and my Silverado and had many miles with loads on them. Never noticed any harshness or any ill effects. Actually, cornering was lot better, as was stability under load.
I took her our for a long drive today. I couldn't be more pleased. Jounce is eliminated. Sway in hard corners is eliminated. Harsh surfaces are dampened.
I have a fairly harsh, washed out section of gravel road near my shop. It was much better behaved over this surface. Seems like alot less is transfered into the cabin.
No noises, no vibrations, nothing. Follows my experience with these on other vehicles I've installed them on. Handles just like a big 'ole minivan now.
Not to say there was really anything wrong with my Promaster as stock. This is just a little bit better. Highly recommended if you frequent rough or unpaved roads.