For the supercharger entrance plastic, I decided to make a new one from stainless steel, for one this plastic is almost impossible to buy, and another reason, it will just break again eventually, one stray air ball and its cracked again.
The brushed stainless steel matches the theme of the area, a highway signpost over the 'road' leading into the supercharger
I just cut it roughly into shape, then used a very thin angle grinder blade to get it very close and finished off with a hand file and dremel.  I then used wet and dry emery paper to rough it up moving in one direction only.