I do not know if it would fit the E90 but this is the best NAV/DVD/Mp3/TV system I have seen so far (All in One)
The Revolution Goes On — the Latest Navigation Systems from Pioneer
Pioneer's AVIC-N2 further improves your driving experience with a multitude of advanced features. The unit keeps drivers better informed — and entertained — with detailed map information for wider area, intuitive touch panel operation, GUI with improved visibility, and CD and/or DVD playback. Additionally, the system is ready to deliver detailed traffic information for major cities in conjunction with the XM NavTraffic service and an optional XM Radio tuner.