SWAG Performance offers a large selection of OEM and aftermarket parts for your 2003–2004 5.9L Cummins engines, including high-pressure fuel system upgrades, electronic tuners, and direct-fit 5.9L turbochargers. Featuring early common rail-specific components, this lineup supports transmission tuning for 47RE and 48RE platforms, plus bolt-on airflow upgrades ideal for towing or track applications.