I have never seen injectors turn blue/brown/purple from the heat like that. EVER.
I don't know how those injectors were still operating.....
and that turbo needs a total 100% disassembly to get all the plastic out.
I have to guess .... what oil was he running????
That oil got HOT HOT HOT HOT HOT!!!!
That part should not melt no matter how hot the thing gets. Should not be plastic.
Nah, you shouldn't tune an engine that's already infamous for blowing head gaskets, plus if the engine got hot enough to melt the plastic and circulate it through the oil system what did it do to the rubber seals in the engine, if the engine had a traditional spin on filter instead of that cartridge with a plastic pickup, would the seal have melted and spewed oil out everywhere?