If it was so easy, the world is such a perfect place. As an "audio expert", some of you here must know that some cars nowadays comes with an integrated system where some car settings are controlled within the same HU. For such a situation, it's not a simple solution of customizing the panel as the HU will have to include the OEM setting (air cond, lighting, alarm etc) which will have to run through a CANBUS. As much as these owners want say an Alpine or Pioneer HU, it's just not possible without the OEM settings.

Yes, of coz the owner can live with it but if that is so, all ICE shop can close. What's the point right if everyone can "live with it"?