Put simply, ignore that link. Its actually the opposite, intakes on NA cars often make no difference or make things worse.
Intakes on the 2.0TFSI have proven gains of upto 18Hp from back to back dyno runs at independant dynos. Particularly so on tuned cars. That said there are other intakes which dont provide the gains and actually strangle the power. Panel filters are also pretty much proven to give negligible gains.
With temp on the 2.0TFSI, its widely regarded that for every 1oC rise in the Intake Air Temp, you will suffer a 1Hp loss of power.
What made sense to me here was I could accept that there is likely to be a degree of heat exchange as intake air passes through the turbo hence they say leaves the turbo en route to the intercooler at ~200 degrees. Would air, say maybe 20 degrees cooler before it reaches the turbo, make any difference if it becomes heated in this way?
On an NA vehicle my point was that cooler air is more beneficial rather than volume of air since there is no intercooling, hence I agree a free flowing filter is only really beneficial on a forced induction vehicle as they volume of air required is inherently higher.
When you talk about intake air where in the system is that temp measured? I would assume it would be somewhere on the output side of the intercooler.
Just trying to understand the science and analysis here!