Get the heavy duty...the comfort version is is basically an improved regular van duty shock. The heavy duty shocks are designed for much more demanding applications such as motorhomes.
I just bought 4 of these...the best price by far was at the Tire Rack.
PPL had them a bit cheaper, but their part numbers were wonky online and I didn't want the hassle of making sure they had the right version or not. It was worth a few dollars more to not have to deal with the incompetent PPL website and the hassle. If they can't get their part numbers and descriptions correct on a website designed in the 90s then I don't want the stress of dealing with them if my order is shipped wrong.