I broke my front XJ mount (single piece) and am now running the Alu 54379. I decided to behave and not buy all of them at once, only as need (eg once the break)
I wish Tamiya had designed the XV-01 to use the same mounts as the TB03/TA05. I have a nice variety of those in my tool box.
I did a comparison, the mount holes for chassis are the same, but the XV-01's are much narrower.