Random thought. I understand that older models had metal shrouds. The p-series on (or maybe earlier) use plastic ones, surely for cost reasons.
What I am wondering--would a metal shroud cool better? I am imagining a metal shroud with fins on the outside to increase surface area, but even without those; the hot air in the shroud would radiate out to the metal shroud and dissipate; the shroud would also presumably touch the cylinder in places, leading to more heat transfer.
Anyone up to making a metal p shroud and testing my theory?