B100 in modern TDis

I am a newbie, so I am probably going to be asking a question that has been answered a number of times. I have a 2011 Audi A3 TDi which shares its drivetrain with the Golf and Jetta. What issues are there with using B100 in the this drivetrain? I have heard two things: B100 has a low flashpoint, so it will burn prematurely in the injectors, B100 will clean all of the crud in the fuel system and plug up the injectors. What is actually true? Thanks.

You shouldn't use anything over B20 in the newer models like you have due to the different emissions systems used in these cars. Even at that level you will need to check your oil level to see if it is rising due to fuel contamination. The emission system uses late fuel injection events to heat up the dpf filter for regen purposes and using too high a percentage of Bio will cause fuel contamination by leaking down the cylinder walls and mixing with the oil. For the states that require B20 use VW says to monitor the oil level for rising and change immediately if noticed. Early on someone here tested this with B100 in a car and it did exactly as VW described. The thread is here somewhere if you care to search for it. Small percent bio causes no issues I have heard of. If using B20 constantly then I would monitor the oil level as described. No way would I be using B100.

As for your other points they are possible as well. B100 does clean things up in the fuel system so anything could get clogged from the filter to the injectors. The injectors on these have tiny holes I am told so they may be inclined to clog either from tiny debris or deposits from burning.

I see you are in Texas like me and some have deleted their emissions system. If you have deleted your emissions system then this becomes less of an issue. If not I would just stick with B20 or less.

Nothing Higher than B20

Here is a very technical reason to NOT use diesel fuel rated higher than B20 in any diesel engine.
https://www.researchgate.net/publication/233002816_Effects_of_B100_Biodiesel_on_Injector_and_Pump_Piston