They aren't extra special bolts you can buy the equivalent at a hardware store M10x55mm 10.9.

(That's from memory it might be slightly different)

You can (as I did) buy 12.9 with some proper locking washers and get unlimited re-use with similar clamping force.

I think maybe captive washer or something doesn't make them worth 10x the price!

One logical compromise that I've seen is to only torque to half the angle (45 vs. 90) but when I looked into that it's a very large drop in force like 40% so cheap normal bolts proper torque is the best low cost option.

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