i found a set of 89 XJ rears that im thinking of purchasing. 30/44 combo. first is the 30 a high pinion for that year? also in terms of strength for the dana 30 how does it compare to the 01 rears i have now? and how do the brakes differ? also im looking at the Vanco Big Brake Kit. it says it fits 90 and up. whats different about the 89 that this kit wont fit?