RE: metal in oil
IMHO.... If that is a new engine... I would not take anything apart but would instead return it and exchange it for another. You can even send a sample of that metal grit exhaust. It is obvious from the goo trail you are running it plenty rich for a new engine. There is obviously something wrong inside that puppy. Is that one of them new chinese made ST? May want to get a TT PRO instead.... a little better engine IMO for racing.
Dan