I just done the opposite to what you're about to do lol. Last week i took off my stock airbox with K&N high-flow panel filter and replaced it with an Apexi Power Intake pod.
I can tell you now that i noticed a significant difference between them. With the pod it feels much more responsive and less restrictive than with the airbox, and the car definately pulls harder for sure.
I hacked at all the air feeds on my airbox when i removed my front bar for the FMIC so i could make an CAI for the box, it helped, but as i said the pod has been significantly better.
I'm not worried about the heatsoak as i hardly ever hit boost on hot days - The only downer on the pod is more unwanted attention, but as of now i'm content with my setup but i'm keeping my airbox in storage in case of any troubles.
Cheers,
Steve.