Air/vacuum leak:
*Intake boots between MAF and throttle valve
*CCV system
*Rubber plugs at the rear end of intake manifold
*DISA valve

That loose hose is front diff ventilation. That's how it should be.

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E39 530dA -02 M-Sport Messing metallic
E53 X5 3.0dA -06 Sport Stratus grey
E70 X5 40d -12 M-Sport Space grey