I remember you mentioning liking the idea of a pointy front end like a rocket, well here is one that already did that.
Subaru itself modded its VW buglike clone the air cooled subaru 360 into a bullet car.
http://ecomodder.com/forum/showthrea...0-a-14887.html
Subaru Drive Magazine: Summer 2006
Given the fact your car is aircooled a bullet car would make more sense than a more effective tadpole shape. Remember though that a bullet car by area is not as affective as a tadpole but it works with your VW motor.
Now the issues, a subaru 360 sucks air from the sides (force vented over the motor) the rocket car tunneled it from the front through the ducting over the motor, your VW would have to be modified in a similar way to get enough air.
Good Luck
Ryan