I installed my hybrideffects.com grille block today. I noticed a quicker warm up, but the normal operating temperature remained at 186F at 48F ambient. It is raining here so I can't quantify any FE gains at this point.
For reference, this is a coroplast version on my old Del Sol from a few years ago.
![](http://img329.imageshack.us/img329/7987/dcp60280tb.jpg)