Just curious, does it have any aero value?

I believe the hood creases offer nothing aerodynamically, but do provide you with a nice sight line for centering the car. I've read more than one review claiming that the purpose of the roof channel is to direct airflow to the lip on the rear of the hatchback lid, but I've also read more than one that said it was simply a design statement (similar to a double-bubble fiat/abarth 750). I've never seen anything substantive from BMW on the aero effect of the roof channel. Funnily, many magazine reviews have suggested that it isn't the channel in the middle as much as the elevated sections on each side that were intentional - to make room for helmets (which I suspect is sales spin rather than reality). :D

Thanks Roland. I will do more research and reading. Do you have any links to provide?

Thanks Roland. I will do more research and reading. Do you have any links to provide?

Nothing that comes to mind - mostly going on memory from all the articles that came out in 3Q07...