Third Mod for my 535xi wagon
 

Decided to change out the rear sway bar because I got such a good deal on it from my local junk yard. Cheap $40 upgrade ☺

I measured the stock xi sways rpughly at 12mm, and the M5 rear sways roughly at 18mm. Noticeably a size difference for sure, and possibly will make a difference.

No fitment issues? How does it feel compared to before?

The rear sway bar went in easy. It took me about 30min to do. You have to use the sway bar bushings for the thicker 18mm. The end links went in the same as before.

The ride is considerably firm, and turn in and out corners are also better. Overall is one of the best $40 I've spent.