Steve,
If you put a high performace filter in the oem box. remove any silencer. Make sure the oem box still picks up air outside engine compartment. IMO,it will do as good or better. The K&N CIA, is open style inside the engine compartment. So it is not really a CIA. You have to get the air from outside to be a true CIA.
I originaly had an open K&N conical, under the hood. It wasnt working out in the hot summer. Underhood heat. I monitored the intake temp with my scangauge2.
I modded the oem box & sealed it. To pick up the air from the fender area and behind the headlight. Using a K&N panel filter. My summer intake temps drop almost 40 degrees.
I also wraped the box, the MAF sensor and the snorkel to the TB. With $1 store heat protector for the windshield. The type that has double chrome vynyl with foam insulation between the layers.
I have an '04. But I suppose you could do the same on an '07.
Not trying to change your mind. Just that my experiance is better performance now. Than with the open under hood filter. I can take a pic if you like.
GL...:driving: