Originally Posted by BabyMakingWeather

Welcome!

The communication system in the latest model BMW's (from the last 18 months or so) is not the same as that in older models, which used a protocol called "I-Bus" for various non-essential components such as the radio, TV and Nav to talk to each other. In other words, it's very likely the new X3 you've ordered no longer uses I-Bus, however as sites such as this one are not up to date yet, you'll have to ask the question on this forum to be sure.

The discussions you've seen about a circuit board relate to ones such Rolf Resler's. These will work in older I-Bus vehicles only.

The older Dension IceLink adapters do not work in the new vehicles for the same reason. Dension have a new box called a Gateway 500 for newer non-iBus BMW's, which now use fibre-optics.

So my suggestion is to hang around a little and let someone else work out the new BMW communication protocol before you try anything.