At 58k plugs are tired.... wouldn't hurt to replace...However, I don't think that will be the issue.

I'd look for vacuum leaks AND clean out any air control valves/fittings into the intake manifold- idle air control valve, etc,etc.

Autoque- MAF fouling can cause air/fuel issues. BMW dealers are morons when it comes to MAFs...they view them as "bad" or "good". Truth is they degrade.

All- Simply get some MAF cleaners and try it. IF IT IMPROVES, then replace the MAF. (Why? The maf cleaner removes the soluble contaminants- but not the oxidized stuff. If your maf improves with a cleaning of the soluble stuff there is undoubtedly oxidized crud on them- a replacement is warranted.) MAFs have a 50k service life, IMO

A