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I can help you with some stuff here though.
1. They say this stuff doesn't really work, and I never used it, so I can't really comment. If you used it before, then stick with what you know.
2. Let the turbo sit 30-60 seconds after you stop driving it. The car's engine fan will come on and run with the car off, if the engine is hot enough. Don't bother spending the extra money for the oil cooler, unless you wanna.
3. Don't know about this one. The link above might help you in that respect.
4. Only use the filter that's recommended for the TDI. The link above might help you with this one too.
5. The TDI's turbo already comes with an intercooler, I think. Again, the link I posted will help you with this too!