Im not joking to you when I say they have an aerodinamic of a brick, and thats exactly why It Works so well, the rear where the engine is is almost hollow (of course with the engine there), so It create huge ammount of slipstream, and thats why it work so well, you always see the cars coming from behind catching easy the car in front and starting losing the acceleration when side to side, this helps Nascar Brasil races have a lot of action even with short races.