[lunarhighway]

i imagine you'll just need some cooling airflow over certain components, so ducting the intake air might reduce the overall drag of cooling. also you could considder creating hood vents so that air will be drawn out when the car is moving, but also as hot air rises it will naturally have a way to escape. a fan is always a safe bet, but perhaps link it to some sort of temperature sensor of manual switch so it doesn't have to be on all the time

also if the radiator is gone you'll have much less flow restriction so i'm sure you can block off some portion of the grill, especially if you'll have the fan as a safeguard