Glad to report that after 1 year (~120hrs) running, the eBay SS U Mixing elbow shows no sign of corrosion or fouling. All i found was some layer of carbon. I know I've micro-soot bubble issue but that from engine itself. Normally after a year with Yanmar stock U Mixing elbow there'll be some hard foul and corrosion of the U. Not anymore. There no photos to show 'cos there's nothing to see!