[brucepick]

I spent some time wondering where/how the cooling system creates drag.

The only thing I can figure is, they would put a complete grill block over the grill and measure the drag vs. "stock" in a wind tunnel. Maybe remove the fan so you don't have whatever turbulence it adds.

If so, then anyone running a grill block is doing much better than the typical car. That's not news of course, but my point is that just because your car still has a cooling system doesn't mean that it's an aerodynamic disaster.