FWIW, you can't have it both ways. If you increase downforce (really lift towards the ground) you are going to increase drag as well. So you can't have more lift, and a lower Cd. From an aerodynamic perspective (BS & MS in Aero), the 90-93 wing design is much cleaner and in fact aids in vortex shedding off of the rear of the car, which _does_ decrease the overall Cd. I can't speak to which wing will have what effect on downforce, as this would have to be tested in a CFD lab or a wind tunnel.