[aerohead]

If I estimate your Honda at Cd0.30 and 19-Ft square frontal area,then to reduce the drag at 60-mph,to that you now experience at 40-mph,would require you to drop the Cd to 0.133.---------------

You're talking about a Ford Probe-V Concept Car.----------------

To do that would require complete skirting of all wheel wells,sealing the front of the car with relocation of the radiator and A/C condenser to the rear quarter-panels,a completely smooth belly-pan,and recountouring and extension of the roofline and rear windshield.---------

You would also need to do active- suspension,where you could lower the car at speed for highway driving while modifying its "rake" for optimum drag reduction. A very ambitious project! -----------------

If you can settle for Cd0.17 and a little less mpg,follow basjoos and what he's done to his AeroCivic.