[bobbyz]

The 2009 idrive control knob can directly replace the '08 version (just need the '09 knob and the '09 center console). The '09 knob will be completely functional. I do not think you can swap out the whole "i-drive system, software" though. As for the rear lights, you would need the '09 lights as well as the '09 trunk lid. I remember reading what your tech says about the wiring though, it will work, but you will have errors lighting up your dash.
Maybe others who have looked into this more deeply can correct me or confirm.