I have had no engine temp issues with the grill blocker. Problem with the external blocker is how to meet function, easy of manufacturing(lots of exposed curves), look reasonably discrete and not damage the OE grill part( SO I can remove it when I sell the car).
The air dam is made from lawn edging, but it is formed. I may take a second try at it. Actually the only problem is how easy it is to drag on a driveway ramp.
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