Implementations described herein relate to features for an integrated aftertreatment system. In one implementation, an integrated aftertreatment system comprises a casing that includes a mating flange having a first constant diameter and a catalyst component configured to mate to the mating flange of the casing. The catalyst component includes a canned body including a first portion sized to a second constant diameter to mate with the first constant diameter of the mating flange. In another implementation, an integrated aftertreatment system comprises a casing, a catalyst component positioned within the casing, a particulate filter having an outer casing with an outlet, and a particulate filter joint coupled to the outer casing of the particulate filter at the outlet. An end of the particulate filter joint is aligned with an end of the particulate filter.