[NachtRitter]

The ALH engines do not have particle traps, and so there is no purging.

Regular diesel fuel also leaves behind deposits in the intake; based on the discussions on the TDI forum, I am not the only one that has removed the ALH intake and found there is only a dime-sized hole remaining due to all the soot deposits from non-biodiesel use. Whether bio-diesel also causes this or not, I would still want to check the intake every time I have to change the timing belt.

Carbon clogging of turbo vanes can also happen with regular diesel; this is not a unique problem for bio-diesel. The cause is driving like a grandma, not the fuel. And the stock VNT-15 on the ALH is less prone to clogging than earlier turbos. Solution to this problem is to drive the car like I stole it on occasion.

Can't speak for the glow plugs; haven't read about these kinds of issues on the TDI forum and haven't had the problem. Of course that doesn't mean there isn't such a problem, just that I haven't seen anything about it.

Despite that possible problem, I am still very much in favor of bio-diesel and will put the highest bio-blend in that I can find (currently B20).

You are right however that bio-diesel is not good for later models of VW diesels (such as the 2011 you are talking about). I still hold out hope that future iterations of the VW diesels will 'play nice' with bio-diesel!