Dale if RK actually shows up he'll bring the best he has otherwise he won't show if he doesn't think he's going to win. If he does show he'll bring the 450 hybrid with the twin intakes, NOS, and electronic override.
What you should do is 2 races; one with the king of the hill bikes your drag set up his 450 hybrid and the second race actual dune bikes, your duner set up against his beater zilla since those are what most resembles what the average guy rides from either builder.