I'm with serialk11r. The difference between the P1 and the time attack cars is the former is organically curved (probably internally as well) while the latter look like an air conditioning duct. Easily fabricated but the un-filleted inside corners are not friendly to the air.
You can probably drop the bouyant lift from underhood heat from the equation without affecting the results.
My suggestion—take a well-proven form like the Volkhart-Sagitta, use a boxer motor for that low hoodline and then put twin radiators in front of the wheels Boxter-style.
