Very nice work, looks pretty, quality craftsmanship.
I am not sure if it will actually do anything as the opening on the Holset is pretty wide and short... FWIW though It looks like something I would obsess over and do if I had the time/tools
You don't think the ring will be forced out when you let off the throttle from air coming back through the anti surge shroud do you? or is it pressed in there pretty tight?
+1 on wanting to see success stories!