While hopping between threads discussing essentially the same thing, I shamelessly believe that my own sketchy calculations on "Importance of the diffuser?", shows just how deilicate this part of the car is.
In a perfect world, to my mind anyway, is that FIA should either impose a "flat-bottom rule", as far as there is a car to measure, or make way for full-blown grund-effects with venturis, siding skirts and the whole shabang. No fans though.
kilcoo?