Answer to the cost of the support kit and name of the arms question:

The replacement idler and pitman arms both run around $70-80 each. MOOG is a top notch brand for these replacements.

You don't necessarily need them, meaning your truck will drive without them, but it will clean up some of the steering slop (where you can move the steering wheel back and forth a bit without the truck actually changing direction). From what I understand, the Cognito support kit just keeps the idler and pitman arm from wearing out much longer than without the support kit. A Cognito rep told me that the arms should be replaced at about 30k miles if you don't have the support kit.

 

They seem to be what everyone uses on the diesel trucks so they can do a 4wd launch