BMW tries to keep it a secret but there is actually less rear headroom in the new 2-series than in the 1-series. The difference is 16mm which is about 0.6inch.
compare (click on magnifying glass next to "technical data") :
http://www.bmw.com/com/en/newvehicle...ata/index.html
versus:
http://www.bmw.com/com/en/newvehicle...ata/index.html
Another secret: despite being much larger 4-series coupe has even less rear headroom by a whooping 26mm which is about 1 full inch.
So in summary: BMW screwed up major with 2-series by making the car larger on the outside yet smaller on the inside where it matters. Yes I know it has more rear legroom but it was ok to begin with (based on my ownership of 1-series) especially with front seats in forward or intermediate positions.