Finally unladen weight figures from BMW in road trim (DIN):
E92 6MT: 1580kg, 3480lbs
E92 M-DCT: 1600kg, 3524lbs (there is a typo on the doc as it is indicated at 1575kg)
Not bad at all for two reasons:
1. The unladen DIN weight for 6MT is below 3500lbs!
2. M-DCT only adds 44lbs!