you have regular stereo with a C43 radio and a CD slot in the front... right? it doesn't say if you have the 6-disk changer but you might, as it could have been installed by a dealer... iBus is a in-car communication link that can roll your windows, turn on/off headlights, display info on the radio screen (MID)... can-bus i think is mostly engine related even though, both of them communicate with each other... there is also kBus that communicates with the other two... there is plenty of posts about all the busses in the car... there is also ibushack yahoo group, if you care to hack into your ibus for whatever reason... there are aftermarket devices based on iBus, like eLights for light controls, StealthOne for V1 radar detector, CIS-IBUS for carPC integration, CP600BMW SD card MP3 player...

as far as ashtrays - typical German approach... when you drive, you can smoke... so, here are 3 ashtrays...
you can't drink and drive, so, there are no cupholders... wait, it was in my E34, no cupholder, but ashtrays everywhere...

since the Gringos (or, is it yankees?) want their cupholders, the Germans put in some cheesy chinese made (or so it feels!!!) cupholders, to keep us happy...