Winglets and bumpy paint?

[lca13]

Without adding any frontal area, one could stop the straight on collision of the air flow and the tires by using a small deflector... it will help but the criteria should be: direct more air outside rather than more inside/underneath the car, do so in such a way as to complement any streamlined flow existing on the car's perimeter (like smooth exstension of lower fender/lip), and make sure it isn't so low that it will rip off/bend on the first pothole or speedbump..

Don't expect to be able to measure the change though. it will be too small, but this and a few other small changes could shave a 1 or 2 or 3 off CD and you will eventually notice.