2.9 xr diffs are the same as a cossie
same front and rear propshafts
2.0 xr4x4 uses the same gearbox, just fork leaver is different
gear box cradle and engine cradles are the same
front roll bars are the same
rears are different
front and rear hubs are different
rear driveshafts are the same
brakes are different
front driveshafts are longer on the xr
suspension im unsure, possibe stiffer springs on the 2.9 xr due to weight of engine
external pump models, tanks are the same

possible other bits aswell