Play is hard to find, you might have a loose universal joint in the replacement driveshaft. Also check your output shafts from the differential. If the half shafts are good then the play is probably the driveshaft.
If you don't really have a vibration in driving then it is a suttle non issue. Unfortunately sometimes there are things you need to accept for an older car. If this issue only came around after the driveshaft I would angle on that issue.
95 E34 530I V2.37
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