Now, expect this thread to show up in Google searches about whether this motor is good or bad.
I did some digging...
The DM950D in use in the Legacy is a Japanese designed and built motor and Briggs only has a license to import and sell this motor in the US and in Europe. So, there is very little "Briggs and Stratton" in this "Vanguard" diesel in our Legacy's. It does not appear to be a Briggs design or even manufactured by Briggs.
There are some reports of weak crank issues with the DM950 non turbo unit, however I could not associate how old these motors were that might have weak crank shafts and I could find nothing that mentioned our motors have these crankshafts.
There are a few reports of motor issues on the turbo version of the DM950
IF one overheats the motor in severe duty use, but I don't necessarily blame the motor for that and we're not using the Turbo motor anyway. Most motors don't like being over heated either...
I've seen mention that the oil galleries are small as Justy mentions above.
When I took delivery of my '11 Legacy, my dealer warned me about the oil fill issue with these motors. You have to add the 3.5 quarts of oil (amount needed during oil change WITH filter change) s l o w l y and give the oil time to make it's way down to the pan. If you dump in 3.5 quarts quickly and then fire up the engine as soon as the last slurp of oil goes in the oil fill, you could damage the motor. My dealer advised me to add oil and just let it sit for 5 minutes or so before turning the key to start and there will never be a problem.
Looks like these Daihatsu diesels are used in Toro lawn equipment and in Kawasaki Mules too as well as other commercial applications.
If these motors are junk and have lots of problems or poor longevity, the internet would be full of stories. I think a well maintained Legacy diesel will last quite a while in a homeowner's hands. I'm not worried one bit about mine. You can find a problem with pretty much every manufactured product in the world that was made by a human. Nothing is completely bullet proof in all applications.