[Matze182]

thanks aerohead, but i have some stupid ideas about the rear.

my thoughts... a boattail is to big. i want to keep my car as compact as it is now.
so, maybe the best solution in this case is something like a box cavity. but with some airducts to reduce the low pressure "bubble" at the rear.
my plan, direct the cooling-air from the engine in ducts through the car and insight the box. this should increase the pressure in the rear.
so this should maybe reduce drag

i know thats kind of stupid, but maybe it works.

what are your thoughts about that.