I use B11 in mine and it runs great. I run it in an '05 Passat TDI also. I like the higher catane/lubricity factor.

It's my theory that the manufacturers are a little gun shy as teh quality aspect is still a little iffy. Especially if someone decides to dump stright or waste veggie oil in. I'm confidant in the 11% soy blend at the Marathon station.

Take Care