Been using Stanadyne since I had the injectors rebuilt. Shop told me this was as good a fuel conditioner as is found. I did notice the vehicle starts easier with the Stanadyne added. Will almost always start on the first turn, with of without using the glow plugs. With the glow plugs it runs much smoother for the first few though.
I would swear that the exhaust has a different smell with this in the fuel. Well, maybe I have been under the hood too long now.