There was a fair amount of discussion about this on DodgeTalk's PW forums back around 2005-2007. My PW is a 2005, and I think they started the full hydroformed frame with the 2006 model year (could be wrong, but that's what I remember). The Dodge factory sliders were available from the parts department of your local Dodge dealer, but they were always in short supply and then they went away completely. There was a vigorous secondary market for factory sliders for a few years, and the factory installation instructions were posted on DodgeTalk at least a couple of times. The factory sliders used only holes that were already in the PW frame from the factory, and there was some goofy spring thingy that came with them that allowed you to fish bolts and crush sleeves into those holes. Apparently it was such a pain in the *** that a lot of guys and shops took to just welding the sliders on.