Having a failing shock absorber on the front left corner created similar problems for me - here in the UAE you can turn right without a signal, so more load tends to go on this corner; fast turns and driving down through multi-story parking made for quite a bit of uneven stress on that side, - previously this caused a similar "brrrrrrrr" noise while cornering to the right at moderate speed, together with ABS warning light. Changed the shock and it was all good.... do you see any tilt in the car's sitting level after leaving it overnight?

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2006 X5 4.8iS (facelift) in Imolarot + Ivory leather & alcantara headliner
1999 E46 323i in Imolarot II + Grey nappa
1990 E30 320iSE Sterlingsilber