w/ the TRD offroad package, you do get some good stuff, like the rear locker. the bilstine shocks, wheels, skids, clutch bypass, 4.10 gears are all nice, too. Unfortunatly Toyota markets it to regular people more so than real wheelers. jon doe would't pay the extra for real skids, sliders, coil-overs, etc, esp. since they all add weight (slower, less mpg).
I do have to say that w/o having a TRD, i probably wouldn't have gotten into the sport (bought my truck to drive, not wheel). Its a good starting point right off the shelf.