Actually the PCM is different in all years with the possible exception of 00 & 01. They are probably different too since in '01 the XJ went to a low emissions standard. Regardless of computer differences (4.0L, 2.5L, auto, stick, t-case option, AC, english, metric, police package) the speedo cluster will interchange. It will also interchange with the TJ. The difference is where some of the indicator light slots are located. 99+ XJ clusters have a rear hatch ajar indicator symbol and they also have a picture of an engine rather than "Check Engine" spelled out. Put the XJ cluster in a TJ and the low washer fluid light comes on when 4wd is engaged (stuff like that) but the gauge dials will still read out correctly.