Will a JCW AL trailing arm fit on a 2004 Cooper S and are the R55 & R56 JCW trailing arms the same?

 

Yes you can put the R56 Aluminum rear trailing arms on an R50/R53. But you will need more than just the arms. You'll need new bolts, speed sensors, and mis parts. We sell all the parts to do it just drop us an email and we'll put it together for you.