That is an observation, it is a reality. It is not an "assessment," an opinion, or a an acceptance of the condition. Luck has nothing to do with a condition we find on many boats. We investigate the problem, measure the extent of the problem then we fix the problem. Re: "You are aware that I am referencing SCR Systems which use DEF and not Soot / PM Filtration devices?" Current and future emissions regulations address SOx, NOx, and Particulate Matter (PM). Selective Catalytic Reduction is just one process for NOx reduction. Full compliance with MARPOL and EPA emissions limits at this time requires both DPF and SCR aftertreatment. SCR is the only currently available technology to meet NOx limits. One cannot take a single component and use that to define or critique an entire system. In practice, the DPF is the component most responsible for exhaust backpressure issues as the SCR catalyst is a "flow through" device which is not a large contributor of back pressure. Adding SCR capability to the system installed by Jorge's firm is a project in progress now and should be available in the near future.