Very clean looking.
I would be a bit worried about the OSB supports (doesn't look like plywood in the pics) rotting from rain/snow/moisture. If the pan proves beneficial, it may be worth a quick trip to the lumber yard to get a 1/2 sheet of treated plywood. also, keep an eye on the zip ties, I've had them break just keeping a grill block in place at highway speeds.
Keep us posted with any results. I have a Ford Expedition myself and it doesn't take an aerodynamics master ninja to see that there is a LOT that can be done to clean up the airflow under the front of a truck. I'm anxious to see if you see any significant increase in mpg's with your Dodge.
As far as warm-up, are you still running a belt fan? Those things circulate a TON of air, even with a clutch. Might be worth looking into an electric setup. Just for a test, try taking it off and running without a fan to see if it warms up any quicker. I know diesels can be a lost cause as far as warm-up (I'm assuming a diesel from your screen name) but surely you can get to temp in less than 25 miles!