I've used B20 in mine on a number of occassions with no difficulties.
The station is far from me and I'm far outside warranty coverage, so I don't want any of the turbidity you're talking about (which I've heard too) gumming up my engine. An injector in the TDI is a few thousand dollars on it's own - that's why it's important to get that fuel-water separator service done when recommended. On older engines, I think it's a better fit as the components are less precise and there's less electronics.
VW has approved the use of B5 in cars, but no higher. B20 is an accepted level for almost any diesel engine now, but you have to be careful in winter as it will gell easier.