Some presents from me:
Floor performance dictates the performance of the car more than ever as everyone know. So i changed my focus to floor pretty early. Extending that vortex that comes from the first two vanes (mostly the first on my case) leaded huge amount of suction and -lift so i tried a lot of different shapes-sizes-locations to enhance it.
Some extras:
surface lic=http://i.imgur.com/6WIYjKa.gifv
These are from the submited Brazil case