Consider how you will cover over (or not) the exhaust system. My belly pan has a crosswise length of exhaust pipe uncovered, so air passing through the "chamber" exits there.
Here's a pic: Scroll down to the last photo in this message post:
http://ecomodder.com/forum/showthrea...tml#post233759
If you have a ScanGauge or plan to get one, it likely can show engine coolant temp. Always a good thing to know, I find, if you're going to mess around with your vehicle. Mine also shows intake air temp, but I don't expect it to show temps at various random spots under the hood.