Added in a meat thermometer to measure the under hood temps with and without the grill blocks in place. Temps didn't change at all with the middle grill block in...so ithe middle block is going to stay fer now. I've changed out the zip tie fasteners with velcro wraps now. Makes it easier to change out as needed.
Added in some side skirts made from some R-Matte along with a belly pan made from a 4'x8' luan panel. The engine bay between the front air dam belly pan and the front cross member is enclosed with some R-Matte as well. That stuff is so easy to work with. Don't have to worry about too much damage if I have an accident as that stuff is just aluminum foil covered foam panel and will disintegrate on impact.
My under hood temps have topped out around 140?F...just sitting still. Thinking about enclosing the battery in R-Matte and venting some air into that enclosure from the front to keep the heat from affecting the battery life down the road.
Just got my best MPG (23.7mpg) on the last tank...driving at 70mph!