It depends if they actually polish the raw material or coat it in a ceramichrome coating.
Oh, and Whipple actually alternates between powdercoating and anodizing their black blowers.
This information is incorrect. The only parts that Whipple anodizes are the snouts, and the old billet base plates. This is because casting does not take anodize like billet does. KB on the other hand utilizes anodizing on their blower bodies because those are extrusions that are machined (you will notice that they leave the front and rear housing bare, or powdercoat those because they are castings).;-) As for whether it holds more heat... obviously PC will hold more heat than anodizing because PC is an actual surface coating like paint, whereas anodize is a much thinner oxide type surface treatment. Whipple has NEVER anodized the finned center section of their blowers because it is cast.