I like to think that engineers are the cheapest bunch of guys you'll ever meet. You know, they wont put anything on a car unless it is absolutely necessary. Therefore, I am very reluctant to remove things installed by the factory. Then again, I don't have any drip rails on my truck because I haven't gotten around to putting them on again. The interior stays dry, but I do bet a little water that pools up on top of the door and drips everywhere when I open it. I think I would have the same problem even if I had the drip rails installed.