Rake has an effect on vertical forces at the front of a 911. Here is some exaggerated windtunel data the shows what 5deg of rake does on the top and bottom surfaces of a 911
the x -axis is the longitudinal position(frnt is 0), Cp is aero pressure coefficient, red is the readings across the top of the car black is underneath, you can see the strongly enhanced negative pressure(suction) at the very front when 5 deg of rake are added. No spoilers are installed
