I had PureTurbos rebuild my dad's 300SD. It was about 375 too if I recall.
Pure Turbos | Turbochargers and Parts | Billet Compressor Wheels | Diesel Upgrades | Rebuild Kits
You could try calling them see if they could do anything like you are after.
Alternatively, you could source a used turbo and have it rebuilt then put it on your car.
Personally, I would rather pay someone to rebuild it and balance it properly than take the chance that I would somehow muck it up and cause bits of turbo to fly through my engine. I am sure I could do the rebuilt but I dont know if I would want to take the risks.
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