I too run M3 control arms, as Dan stated there are no issues running a non-M sway bar mounted to the control arms. The M3 control arms have the same mounting hole as the non-M control arms. The U-bracket unbolts from the old control arm and bolts into the new one.
And as Dan mentioned there are some geometry differences between the 95 and 96+ M control arms so be aware of what you need in terms of control arm bushings.
Both inner and outer ball joints on the M and non-M control arms are replaceable despite what some manuals say. I'd assume BMW just wants you to use fresh arms to keep old again ones from failing.
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