I wouldn't pick on the cat engines I work on all types for a living, weather its cat deere cummins or Detroit there isn't much other than filters on the aftermarket any more. The dealership parts are expensive. T,he only draw back I see for cat is you cant even go to napa and buy gaskets anymore even though victor renz makes them for cat, part of the deal is they cant make them for the aftermarket. you cant compare the c series cummins to a b series either there is truly aftermarket support for the b series which has likely been an all time most desirable engine platform for swaps aside from the sb chevy.