Intake air boot: #4 on this diagram: RealOEM.com BMW E53 X5 4.4i Hot-film air mass meter

Vaccum lines: You have the choice! There are many, at least 2 of them come to the intake boot

Maybe you should check also the state of the OS hoses: RealOEM.com BMW E53 X5 4.4i Crankcase-Ventilation/oil separator

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BMW X5 2001 3.0I
ALFA-ROMEO Mito Turbo-Jet
Many mythical italian brand Laverda motorbikes...