I remember phil mentioning that you shouldn't have them polished or powder coated too mate. Phil got it polished on my car though so it is possible
It is possible to polish, but the hit rate is quite low, which is why he never offered it. He sent a few away, and some came back working, but some didnt. They couldnt work out why IIRC so didnt offer it as a service to customers. PC it, I dont know, but wouldnt expect the heat to play nicely with the electronics in the throttle.