I recently installed these on my truck. I've been very happy with them:
Monroe Gas-Magnum® Truck
http://www.monroe.com/products/gasma...ject+Object%5D
I tow without a WDH and found that the weight (close to max GRAWR) on the rear of my truck caused some bouncing issues. These shocks make the ride much more comfortable while towing without effecting the non-towing ride.
***I also have "Air-Lift" air-bags on my truck.