Based on the one being abused I'm confident the rest were as well.

The stiffening plate makes the car rigid, if the bolts aren't stupid tight it's not performing it's duty. If the bolts were reused and torqued they can't be torqued properly after ≈ twice as they will be plastically deformed.

I did destructive testing on a handful of these bolts. On the third tightening every bolt failed; no longer could tighten, could feel them stretching before I could TTY.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)