Road Kings are great. Very pleased with them on our Country Coach.
Koni usually has two models to choose from:
-FSD - If sized properly for your chassis, improves the ride whild
still dampening. Unique to FSD, the dampen on the rebound, vs
the compression down stroke.
-Adjustable - Just be sure it is the SP3 generation, as SP2's are
still being sold.
Bilstien - Choose carefully on these, but they are suppose to have
some new ones out with different valving.
And the, the rest like Monroe, and private label items for Sears, Wall Mart, etc.
I have found that if you call with the info on your rig and chassis, that Henderson's Lineup gives pretty good advise.