As still listed on the alternative parts list here: https://www.dropbox.com/s/cvo7sehb6o4q9la/Updated%20List%2011%20June%202019.pdf?dl=0. Page 5. Unless you can see movement in the comfort kit spherical bearing I don't think that replacing it will make any difference Austin. If it is the same as the others, the clunk is in the bush at the LH end of the rack. M3W55 has had that bush replaced recently and will hopefully supply us with some info about it soon?