XJ, MJ, TJ, and ZJ front upper and lower control arms are interchangeable, and all the same length (ie: they're the same arms).TJ front and rear LCA's are also interchangeable and the same length, which means TJ rear LCA's are also interchangeable with XJ/ZJ/MJ front LCA's.I don't know if ZJ LCA's are interchangeable front to rear.TJ UCA's are different front to rear, as are ZJ UCA's (I think). I don't know if TJ rear UCA's are interchangeable with ZJ rear UCA's, but I don't think that they are.WJ front LCA's are interchangeable with XJ/ZJ/MJ/TJ front LCA's with a little modification/grinding to the arms. I don't know if WJ arms are a different length than the XJ/TJ/MJ/ZJ LCA's or not.Basically, any LCA's will work, but if you want longer ones, you either have to build them yourself or buy some.