Use PFR5-325 for all models where the bush is in the subframe - M3 models upto 1996. PFR5-324 fits later M3 Evo models where the bush fits into a separate mounting bracket.
PFR5-4025 is a replacement bush that includes aluminium sleeves with built-in support to increase control of rear diff movement and replaces all four bushes in the original rear diff front mounting...