Problem with the foxs is theres very little to no rebound dampening because of the giant free bleed holes on the bottom of the rebound zone. The kings are only 2 zones but its a transitioning zone because of the tapered needle..the 3.0 kings I replaced my factory "3.0 s" with ride a whole lot better and I got a true 3.0 sized piston rather than a 2.5 in a 3.0 body with the fox. Also 2 compression stacks of shims and 2 rebound stacks of shims making them almost infinitely adjustable. The wholes drilled in the fox inner body doesn't leave much adjustment, even though they are shimmed.
Those bleed holes in the bottom are not bypass holes, they are what make the reservoir bottom mount (fluid that the shaft displaces goes into the reservoir from the rebound side of the piston, greatly increasing compression damping effectiveness). They are only bypass holes if the fluid recirculates back to above the piston, which it does not do. Additionally, any offroad truck you want the rebound to fire pretty hard from ride height anyways. Like, the last truck we tuned the suspension almost bounces off the limit straps if the truck comes off the ground fast enough.
You're hung up on "true 3.0" when in reality, due to the design of the Foxes, they are within about 5-10% of the total damping ability of the king due to using the shaft for damping (by making the reservoir bottom mount and controlling flow into/out of the reservoir with a shim stack and the DSC valve) where king does not do that. And then due to the design of the foxes there are more bypass stages. All of which are just as tunable (if not more tunable) as a king if you know what you're doing. A 2.5" shock is much more capable than a lot of people think, having the additional bypass stages is more important than going from a 2.5 to a 3.0 and only having two zones in the 3.0. The twin tube IBP's are definitely better tech than needle shocks from both a tuning and ride quality stand point. I'm sure the kings ride better than the factory foxes, but the factory foxes are setup for a wide range use, where as the kings are much more focused in how they perform.
And on the subject of tuning, 99.9999% of dudes on this site aren't going to take apart the shocks and tune them. Both the kings and the foxes are set up very well from factory, and the clickers on the fox allow a fair range of adjustment for high and low speed damping to suit different guys' driving. The king also has an adjuster. So talking about tuning beyond turning clickers is mostly a moot point.
Hell, I took all of my foxes apart before install to replace the garbage Fox fluid with what we use in the race trucks, and I was thinking I may make valving changes. Well the piston in the rear 3.0's was already pretty much stacked, and I liked what I saw on the piston in the fronts so i left that as well except for making some very small adjustments to account for the different fluid being slightly thinner (changed a few things around on the fulcrum and the largest shim by a about .005").
