First I disagree with the being modded and intake statement. OEM Induction systems are hugely restrictive in most applications. The air requirements for an engine are huge. I used to have the numbers somewhere and I'll see if I can dig them up again. So whether you are modded or not, the engine will ALWAYS benefit from better air flow.
Aftermarket systems that use lots of piping, more specifically piping with lots of bends or large degree bends are going to be a huge hinderence to air flow. ZZP did some testing that showed this. Essentially, anything less than straight into the TB is going to pose a restriction. Every bend in an intake system, no matter how small will have an impact on total air flow. Any change in angle is going to affect air flow.
The question then becomes is it better to have higher IAT's with higher air flow or reduced air flow with lower IAT's. Considering that the air goes straight into the blower that is its own source of heat cannot see that it would really matter in the grand scheme of things.
Furthermore, there is air flow over the headlight. Yes, more so when you remove it, but our headlights are not sealed off from the outside. So if you do have a HAI on, at speed, you are going to get some cooling effect. Now if you stop and idle a lot such as you would with city driving, I can certainly see this being an issue, but if you are in the city where there is frequent stop and go traffic, I doubt you will be getting into boost a great deal.
Im not induction expert, but just thinking from the common sense side of it, I think the choice in intakes depends on a few factors:
1. Your driving habits (as mentioned above, all city, all highway, or combo)
2. Esthetic's (which is cooler, the $250 FWI, or the $40 short ram HAI intake)
3. Installation difficulty and maintenance.
Of course cooler denser air would be more beneficial than warmer air but I know of no application on the market in which tapping into that cooler air doesnt introduce some bends and angles that reduce overall flow.