I was at school last week doing some datalogging on my truck with a Snap On Verus scantool. For the hell of it, I decided to check IATs with and without the driver's side headlight installed, since I have a K&N CAI installed. Coupled with the hole in the core support being right in front of the filter, it made quite a difference. It was about 50* outside during testing. IATs with the headlight removed were close to outside air temp, usually within 5* or so. IATs with the headlight installed were 20-25* warmer during WOT. So it looks like I'll be pulling my headlight next time I go to the track.