Went to a Cummins engine seminar at the spring FMCA convention in Perry thinking we might learn something useful; problem is, the presentation started with ISC and what we learned, or re-learned, is that most 'progress' in engine design since the mid-1990s have been made to offset increasingly rigorous emissions standards.
As much as we love our all mechanical, low maintenance Cummins, though, we are not against the progress that has been made -- in the long run, we will all be better off with the current crop of lower emitting diesels!
So in answer to the original post, it may hard matter which model year is chosen for a used diesel Class A, so long as the coach is is good shape and floor plan favorable. One is not penalized for buying an older coach from a performance point of view, at least from the '90s onward. In fact, when our chassis suspension assessed at Perry, the mechanic driving the coach was really impressed with its power and handling.
