I know, it would obviously be ideal to have all these comparisons! I asked Brett about your comment above.
His reply: This shouldn't be an issue, this is why you use aluminum for intakes and intercooler pipes. We use aluminum to eliminate any chance of the system rusting, and it's lighter than steel. One down side to plastic is that it absorbs some of the sound energy people like to hear. Whether or not an inlet system is made from aluminum, steel, or plastic, the thermal conductivity of the duct material has little effect on engine power. The rate at which air travels through the inlet path under open throttle, when one is asking the engine for maximum power, negates the effect of material heat soak, regardless of the material.