[Ecky]

I'm planning to install a belly pan in the next few days and I'd like to know, what's the most aerodynamic way for air to exit the engine bay? Should it be coming out at the rear of the hood over the windshield or should I block this spot off? Should I be plugging the holes that would let it vent through the wheel wells? Should I have an opening in the bottom of the pan at the rear of the engine bay, perhaps with some fins to smooth our airflow as it exits?

Are there any major difficulties I should be aware of, other than the exhaust pipe?

I've hit the search and read most of the old threads but I figure it doesn't hurt to ask.