I think that by this point it's a given that if this is the engine you will be keeping in the car you must remove it and have the whole assembly torn down. The metal you've seen in your
oil has run throughout the whole oiling system and undoubtably comprimized most components, from the cam bearings on out. I think it's better to start planning your new engine(you mentioned stroker) rather that worry what caused it or who's to blame. I can tell you what caused it without even looking at it-carelessness during assembly. No one will easily accept the blame for the failure and most likely lay the blame on "abusive driving" especially if they get wind of your n2o system. You will just be stuck looking for someone to choke while your Cobra sits in pieces. You still have alot of good parts, now build YOUR motor!
RACING!-because baseball football basketball golf bowling & tennis only requires one ball. Just trying to get you to laugh...