Wow, what a mess. I would start by measuring your valve recession and piston protrusion on each cylinder to make sure theres no variance there, Ive already talked to Justin and he confirmed the cam is installed correctly. Was the block or heads ever media blasted? Maybe there was some media left in the engine. What does your air filter setup look like? I don't think you were blowing the 910s open even with them unshimmed, I've run more boost on stock springs without valves making imprints, but they definitly start to float around 25 psi. Granted, that was a stock cam but I think if it were the more aggressive cam causing them to float you would see imprints on every piston. With it being on some, theres got to be a variance somewhere in the machining or valvetrain that is causing certain valves to hit. Can you pull the housings off the turbo and post pictures of any wear on the wheels? That would help show where the wear is coming from, the cylinder walls look terrible for the amount of miles. The single burnt glow plug is odd, have you pop tested the injectors?