ride it up on ramps and use an infrared thermometer to see how much the local turbo temps are reduced. This would be the best way to see if it actually helps.

My question is does circulating 200ºF coolant through the turbos and heads really do anything vs. 212ºF coolant just laying there? Theoretically it should do something.
What is the coolant to local oil temperature association?
If the afterrun coolant is normally circulated at 234ºF what turbo local oil temperature does this coerrelate to? Perhaps this correlates to a significantly higher local oil temperature, and deemed more of a threat by Audi Engineers, but at 200-212ºF coolant temp the local oil temperature is deemed safe.
At any rate synthetic oil won't truly coke like dino, and can handle the high temperatures much better.

Don't get me wrong you've got an excellent writeup there, and your investigation to find the parts was very well executed, but I question whether or not it truly helps much at those temperatures.

Future:
2009 A4 2.0Tq Tip
Prestige
S-Line
Monza Silver / Black
Drive Select
Nav

Present:


Past:
2001 B5 S4 6spd