Here is some of the info from the link below but your have to read the full thread.
Sorry for the late reply folks. Been flat out. Right, here we go. Note the measurements are the temperature of the air, not the 'amount' of free flowing air getting in. The thinking being that colder air is better as its more dense and oxygen rich.
Some interesting findings:
General outside ambient Temperature at time of runs was 3-4°
1) Standard Air Box. with ITG panel filter -
Temp during the short run at normal road speed - 24°
Temp range during logging 2k-6k run -: 17° to 9°
2) Aftermarket cone filter in engine bay, direct cold air tubing to cone from front lower grill, and large bonnet scoop vent above cone filter
Temp during short run at normal speed -: 22°
Temp range during logging run 2k-6k -: 12 to 9°
3) Carbonio Cold Air Intake
Temp during short run at normal speed -: 6°
Temp during logging run 2k-6k -: 6°
The Carbonio was by far the coldest at all RPM\speeds. It had the lowest difference from ambient temp and maintained it even when the car slowed down.
The cone filter in the engine bay suffered from a degree of heat soak. Less so at high rpm\speed levels. Helped by bonnet vent and ram tubing which most other users don't have, so expect worse performance if you only have a cone in the bay. As the car slowed the intake temps rose steadily back up.
The OEM airbox suffers from massive heat soak, and didn't perform until very high speeds when lots of air was flowing into it. But as soon as the car slowed the intake temp went up very high again to well over 25° in just seconds.
So the conclusion seems to be that the Carbonio rejects heat soak more than the others tested, and allows for colder air at a wider range of speeds.