On my '08 535i, with the 6FL option, which likely has the same software as the E70, the interface worked well. It was much better than using the iPod handheld (which is illegal here anyway). Steering wheel controls for navigating the menus, and iDrive display of the song details.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue