what i'm lead to believe is that it lubes the pump injectors etc. and cleans out the carbon in the cylinders, ( it makes the combustion hotter???) not sure if this is true, but then thats pretty much the claims of 2T isn't it ?
personaly i use http://www.moreyoil.co.nz/moreys-diesel-smoke-killer/ it has cut down on the amount of smoke i blow out the exhaust. have used a additive similar to this since the mid 90's, i have over 500 000 kms and not touched the fuel system except filters