Originally Posted by m3h
2011 (March 2010) - E92 LCI (LED tail lights), competition (ZCP) package
2011.5 (Sept 2010) - combox for CIC iDrive with standard bluetooth (6FL), mineral white, manuals seat option, two tone seats, standard mdrive (incl. MDM)
2011.75 (March 2011) - BMW apps (6NR), auto start/stop
Build date for the more expensive base priced E90 above is May 2011 so it's a 2011.75.
This is a pretty good reference. Combox on 2011.5 fyi added Bluetooth audio streaming and Office (texts and emails displayed on iDrive if you have a BlackBerry or iPhone). However, Bluetooth did NOT become standard for 2011.5; COMBOX became standard IF you got Bluetooth.
Also worth noting is that for 2011.5, the Technology Package was replaced with the Convenience Package, which had slightly different contents because the Tech Package was split off between standard features and the Comp Pkg. The Convenience Package was then deprecated for 2012 since its features either became standard or integrated into the new Premium Package, which also got additional contents not part of either the earlier Premium Package or the Convenience Package (e.g. rear sunshade).