Once again, not calling you out.
IM "opinion," it's true- plastic is a better insulator than metal. It's also cheaper to use, especially after you figure in coating the metal to resist heat. So why doesn't everybody use it?
It cracks. Plastic is incredibly prone to expansion and contraction in response to temperature changes. If you live in a climate that tends to get colder, a cold plastic intake being rapidly heated in the engine bay is bad news for the plastic. I don't know exactly where skull island is, but here in Colorado, nobody uses Iceman intakes because we've all seen more than one with a fairly sizable crack due to wintertime driving. The plastic used in the Iceman is especially prone because it is such a hard plastic. The stock airboxes and intake tubes aren't as prone because they're a much softer compound. True, this doesn't apply to everybody, but if you live in a climate that sees more than 4 months of snow, it's something to keep in mind.
Finally, consider this:
Given: 18.1 hp and 12.6 lb/ft is an incredibly lofty number. However, I've never even heard of Iceman even claiming these kinds of results. Also, a dyno is only as good as the people performing it, and I can't say anything (good or bad) about this dyno or these people. So if the materials/ insulation on the Iceman is so much better and the charge air is so much cooler, where are these massive (or at least comparable) gains coming from? The AEM is dyno proven to outperform every other intake on the market. Given: I have yet to see a head to head of the AEM vs. the Iceman performed on the same car on the same day. Even then, whichever was tested first has the advantage. If anybody does know where I can see one, please let me know- I'm very interested.