Rotate the axles, if no clicks, then reboot them.
Buy the GKN boots from FCPEuro etc.
The GKN axles typically last some 300K miles, if the rubber boots are not torn.
The #1 cause of failure is always a torn boot.

If car owners routine replace the boots at let's say every 100K, there will be no market for aftermarket axles. The problem with axles: out of sight out of mind.

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1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT