Car PC with CarX is connected to the RearviewCamera input, the i-bus command (when swithcing to tape) is going to togle the system to switch to RV Cam imput and you will get CarX Menu on screen. Now when turning the knob you can control CarX.
I am not sure, but it should be possible to hook the CarPC with CarX instead of the CD changer witch i guess that you dont have.

Anyways the answer is NO, if you chouse CarX then CD/Tape got to go or CD Changer.

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X5 4,4i-06 Current
330Ci Cab-03 2007-2008
MB E55 AMG-03 2006-2007
Z3 2,8 Roadster-98 2006-2007
X3 2,0d-05 2005-2006
320d-99 1999-2005