S300/S400 Compound Turbo Kit for the 2003-2007 5.9 Cummins are a step above the typical S400/Stock combination. These Kits can be used for extreme towing with the properly spec'd high pressure turbo, or built to exceed 1200 RWHP. If you are not buying a manifold and turbo chargers from us, you may be required to send your parts in for us properly mock up and build the kit. Every WCFab Turbo kit is hand build in house by our experienced fabricators and welders and every component is built and test fit on our jigs to ensure proper fitment. Unlike many other kits on the market we do not use boot connections between the turbo chargers, only v-band for a boost-leak free setup. All tubing is TIG welded and the mating flanges are CNC machined with O-ring seals where necessary. We stand behind our fabricated components and workmanship for the life that you own the product. The Compound Turbo Kit comes with all the necessary components to install, with several upgrades and turbo options available.