Not really - drag is proportional to velocity squared. There's little penalty to driving a brick at 30. You can feel the wind resistance on a bicycle at 30km/h

Not really - drag is proportional to velocity squared. There's little penalty to driving a brick at 30. You can feel the wind resistance on a bicycle at 30km/h, mind. The penalty is not zero. But we're discussing body styling for a given frontal area, so the possible improvements are more marginal than for a cyclist who adopts a racing tuck.