So I fitted a grill block that goes behind the grill. Undetectable beyond 3 feet away. I tested engine temps just to be sure and they of course were virtually unchanged. Cool beans.
This morning there was a slight side wind breeze ~10km hr, I was hoping for dead calm but wind actually increased to 24km/hr by the time I got to my destination 63km away. To complicate things further there was a small detour slowing to 60km/hr and then back up, but my results from a pure highway run (from the moment I hit the highway 4 to the moment I left it was 4.8L/100km (58.85 mpgIMP)(49.003mpgUS) & that is on varied terrain. I tested on what I thought was a pure flat section, my results were a little surprising at 4.1-4.3L/100km for about a 7-10km stretch with cruise on.
Spurred on by these results I am going to be picking up some duct tape and making flat wheel covers out of the Prius covers tonight. I may have enough chloroplast to make a front belly pan (going from the front bumper to the front cross beam section between the front tires) so I might try that too depending on time.
Not bad. Way past Yaris and Fiesta SFE territory...if conditions are like they were today...the new PriusV and C better look over their shoulder...(well EPA ratings anyways :P.)