I would pull that motor, and throw the bottom end in the garbage. Tear down the heads and your block to ground zero. Start fresh from square one, that way there is nothing to question except yourself (it very hard to trust anybody when it comes to building engines).
I would definetly get something in writing about the 'performance engine' only having a spun bearing....that way if when you peel it apart and find other issues you at least have something to fall back on.
what are DSP super T28's? sounds like dinosaur technology to me....