asumbing the mythbusters data is correct (i believe it is)

im betting their are two main reasons that car manufactures dont put dimples on a car.
one reason...looks
their have been a lot of cars out their that look really weird but perform well, they never sold because they were so strange.
reason 2....cost
it would cost a lot to dimple a car, parts would have to be moved, new machines to make the dimples, some space would be lost, ect.
the manufactures dont care how much we have to pay for gas, if the retail price of the car increased by a few grand that may be enough to scare people away from the design.

and thats just the main reasons,
how much fun would it be to clean a car with dimples? or what happens when it rains and the dimples are full of water or snow or leaves or mold, ect? how fragail would the design be?
the argument, if it worked so well we would all have dimples on our car, is not valid. their is a lot more to it.