warm air and warm fuel is for top efficiency so it atomizes. the microfiber doesn't reduce performance, normal oem air boxes are made to be restricted. it takes less throttle not more throttle, the point isn't warm air intake its a less restrictive air intake with a good filtering process.
You are contradicting your source.
This is the source you quoted from:
All warm air intakes operate on the principle of decreasing the amount of oxygen available for combustion with fuel. Warm air from inside the engine bay is used opposed to air taken from the generally more restrictive stock intake. Warmer air is less dense, and thus contains less oxygen to burn fuel in.
The car's ECU compensates by opening the throttle wider to admit more air. This, in turn, decreases the resistance the engine must overcome to suck air in.
The net effect is for the engine to intake the same amount of oxygen (and thus burn the same amount of fuel, producing the same power) but with less pumping losses, allowing for a gain in fuel economy, at the expense of top-end power
Many of us use CAI systems on our trucks and can assure you they are less restrictive than the OEM air boxes. However the air box isn't that restrictive with a good replacement filter, but the Hat or noise suppressor is. You are still using the most restrictive part of the intake system.