When DW and I end up with a sack of questions we end up going to our dealer where we bought our trailer to talk to the folk in person. We're strolling up to the parts department when we take note of this monster trailer. They had this humongous triple axle Escalade that we *just* had to take a tour of. I swear this monster was about 38 feet or so and I commented that I probably couldn't pull it with F-250 4X4. Well, the sales guy came right back and said that I could if I added the "Ride-Rites" to our truck. Said that they would increase the carrying capacity of truck bed and when I looked them up, they say they can accommodate 5,000# a pair.I have not installed these on mine either, but have looked into the ride rite before. I believe that would be a great choice as well.
I wouldn't say that you "need" them unless you are experiencing rough rides, but they would be a good add on.
I don't know of anyone we camp with that has added these to their tow vehicle, and some of them are towing 37' 5th wheels. I still think it would be a good addition, but you may want to try out towing it with a full load to see if its really something you need.
I'm seriously looking into them anyway, not that we're going to buy that Escalade but just to make sure we're not exceeding the limits of the truck. I don't know about anyone else but when 4 of us go starhopping, we come pretty well packed with luggage and scopes. I'd even venture to say without weighing the truck and trailer we are pushing the weight constraints.