Bunyan: That is the battery for the Shimano DI2 electric shift. Actuator motors in both the front and rear derailleurs, pushbutton shifting, automatic trimming of the front derailleur with rear chain position. Shifts under full load, by automatically overshifting then trimming back to a running position. Very cool. Still a bit pricy for the rest of us peasants.

AZX54.4: Bike looks good, thanks for the pictures. Need to watch that focus on the close up shots! Interested in why the Mavic brakes, or is that just the way the bike shop had built it up?

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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