Looking to purchase new brake rotors, and I see that some are 305, and some 325 mm. Are these interchangeable? Not much of a size difference, ~3/4" so what gives? I'd rather get some ordered rather than take it apart to get a accurate measurement and then wait around for parts.

 

believe 305 is xj8, 325 is non-brembo xjr and later xj8 sport