I installed the Dexter EZ-Flex on my last 5er with the new wet spring bushings(Greasable) and new links. Made a huge difference in the ride. I have shocks and air hitch on my present 5er and I think the EZ-Flex road a little better. Cost would probably be similar and the EZ-Flex isn't real hard to install. Takes about 4 hours a side working by yourself without rushing. If you want to have any more details give me a PM and I will answer any questions that you may have.
03 Silverado cclb 3500 drw, D/A, Reese 22k hitch
07 Alfa SeeYa Gold 30RL,2 slides,power everything