I looked into this a couple years ago when I thought a mopar 5.2 or 5.9 swap might be good into my cherokee. I did not come up with anything except that you needed special hardware to program the PCM's and startup costs were in the $3000 range. So basically unless you were doing it on a shop level where the hardware and software would pay for itself its not DIY friendly. I did not find anyone disassembling the chips either...