Is that $400 before of after you install the hardware? As far as I've seen so far, you can but the parts and install them yourself but the dealer has to flash the computer. I think $400 was about what the whole setup cost when I looked into it. I didn't look very hard though and it was a few years ago.
2010 KK Sport, Detoures Knucklebone & backbone, smittybilt XRC 10, rigid led lights, R/L sliders & rack, cb, EMT2, R/K 15x7, OME, JBA, mopar skids & hitch, headlight covers, 4.10's and TruTracs