fueling systems prime when the car is unlocked, and the water pump flows upon shutdown to cool things down. If you sit inside the car when it has been turned off, the CD player unit makes all sorts of noises. I have no idea what that’s all about. I've sat in N54 powered E9xs, E6Xs, and E8Xs, they all do it.
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586r Tial .82AR/Motiv Port Fuel/Meisterschaft Race/Berk Resonated/ER CP/Synapse/VRSF FMIC/Rob Beck PCV Valve + Cap/ST Coilovers/M3 FCA + Tension Rods/M3 Subframe Bushings/M3 FSB/AA Strutbrace/DINAN Camber Plates/Apex ARC-8/Project Kics/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/#Tee CF Stuff/Kerscher/BMW Performance