I understand these facts, I am in fact an engineer for a fluid system components manufacturer (fittings, valves, tubing, pressure regulators, etc). The potential for gain is there, however there are multiple threads, videos, and articles with test data showing that gains are minimal, if any, compared to stock systems with the same running conditions. If you have any data sources to prove otherwise (that doesn't come from a product sale page), I'd appreciate a link. Not being rude, I'm genuinely interested to see the numbers.
Most intakes are still drawing in air from the same spot as the stock intake, same temperature. You can only pull in as much air as the system pushes out (continuity equation of fluid mechanics). Continuity does not apply to compressible fluids however, which is what leads to things like turbo flutter. At some point, the size of the intake does not matter because no more air will fit in there.
The stock intake system is likely engineered undersized so the potential for gains can be had. If you route the intake out of the hood, or into a completely heat-shielded and compartmentalized portion, I could definitely see some theoretical gains.
