I am in the process of getting ready to install a CarPC in my X3. I purchased a GNET Video module and purchased a MiniPc. I put a digital tuner (minipci) inside of the MiniPC. Works well with antenna that came with it. Not sure yet how it will work in the X3.

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E83 - Aero PKG Mods installed: Homelink mirror. CIS-IBUS video module, AUX, Rr Dr Release, stock wheels, Remote start, CarPC (Atom) & mud flaps - NAV - MKIV - NA Map DVD - 2011
E46 - 18.5 wheels/tires (summer), 17 stock (winter), Homelink, NAV software upgrade, BMW video module, Radio to V53, AUX, USB IBUS interface,BMW alarm install, CarPC(Epia), remote starter, tank battery & angel eyes. NAV - MKIII - NA Map CD - High Version 2008.1