If you remove the two good bolts, good chance you can extract the other two with the few possibilities, then get four new bolts before you likely stretched the two remaining bolts. The hub is open in back I'm sure there is extra room for four mm so a 20mm bolt would work or a 15mm also would likely work.

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