All the ones you showed are not getting air from outside the engine bay. They may have their "heat shields" in place, and they may be positioned to get air coming into the engine bay, but they are still inside the engine bay and still pulling in hot air from the engine bay as well as what cold air happens to flow into the bay. They are not completely enclosed, and those heat shields do not really seal up when you close the hood. And as it flows into the bay, the air heats up, so you might be getting slightly colder air, but not enough to really help.

Take a look at the Volant kit, for example. Enclosed filter, once you plug up the hole designed for the optional front scoop. It only gets its air from the wheel well. No way for engine bay air to get into it (unless, of course, you don't have it sealed up right).

Do me a favor and just glance at the other threads on this topic. Others, more experienced than I, have already explained the science behind this. One gentleman even had a K&N FIPK, switched to the 14x3, and noticed a bit of a power gain.

 

like i said i got the last one on the list, and when i installed it i made sure there was no engine bay air coming into it by adding a little bit of foam around the edges and on the hood, so it was just getting air from the fender duct. i had the 14x3 and yes it did have a little more power to the one i have now at WOT, but i am never at WOT anyways. I just couldnt stand the loud wistle and pornstar sucking sound it had. still got it sitting on the workbench now.

i might actually have to throw it on soon and see if i can tell a true difference again!!!